Merge branch 'v4-dev' into btn_input_split_variables

42 files changed, 28 insertions, 28 deletions

diff --git a/docs/4.0/examples/blog/blog.css b/docs/4.0/examples/blog/blog.css
index 0f319ec92..e4381fec6 100644
--- a/docs/4.0/examples/blog/blog.css
+++ b/docs/4.0/examples/blog/blog.css
@@ -47,7 +47,7 @@ h6,
 .blog-masthead {
   margin-bottom: 3rem;
   background-color: #428bca;
-  box-shadow: inset 0 -.1rem .25rem rgba(0,0,0,.1);
+  box-shadow: inset 0 -.1rem .25rem rgba(0, 0, 0, .1);
 }
 
 /* Nav links */
diff --git a/docs/4.0/examples/cover/cover.css b/docs/4.0/examples/cover/cover.css
index 2b208671b..96a89740b 100644
--- a/docs/4.0/examples/cover/cover.css
+++ b/docs/4.0/examples/cover/cover.css
@@ -32,7 +32,7 @@ body {
 body {
   color: #fff;
   text-align: center;
-  text-shadow: 0 .05rem .1rem rgba(0,0,0,.5);
+  text-shadow: 0 .05rem .1rem rgba(0, 0, 0, .5);
 }
 
 /* Extra markup and styles for table-esque vertical and horizontal centering */
@@ -41,7 +41,7 @@ body {
   width: 100%;
   height: 100%; /* For at least Firefox */
   min-height: 100%;
-  box-shadow: inset 0 0 5rem rgba(0,0,0,.5);
+  box-shadow: inset 0 0 5rem rgba(0, 0, 0, .5);
 }
 .site-wrapper-inner {
   display: table-cell;
@@ -73,14 +73,14 @@ body {
 .nav-masthead .nav-link {
   padding: .25rem 0;
   font-weight: 700;
-  color: rgba(255,255,255,.5);
+  color: rgba(255, 255, 255, .5);
   background-color: transparent;
   border-bottom: .25rem solid transparent;
 }
 
 .nav-masthead .nav-link:hover,
 .nav-masthead .nav-link:focus {
-  border-bottom-color: rgba(255,255,255,.25);
+  border-bottom-color: rgba(255, 255, 255, .25);
 }
 
 .nav-masthead .nav-link + .nav-link {
@@ -120,7 +120,7 @@ body {
  */
 
 .mastfoot {
-  color: rgba(255,255,255,.5);
+  color: rgba(255, 255, 255, .5);
 }
 
 
diff --git a/docs/4.0/examples/grid/grid.css b/docs/4.0/examples/grid/grid.css
index 5f7e1af66..78f5dfda6 100644
--- a/docs/4.0/examples/grid/grid.css
+++ b/docs/4.0/examples/grid/grid.css
@@ -17,8 +17,8 @@ h3 {
 [class*="col-"] {
   padding-top: 1rem;
   padding-bottom: 1rem;
-  background-color: rgba(86,61,124,.15);
-  border: 1px solid rgba(86,61,124,.2);
+  background-color: rgba(86, 61, 124, .15);
+  border: 1px solid rgba(86, 61, 124, .2);
 }
 
 hr {
diff --git a/docs/4.0/examples/index.md b/docs/4.0/examples/index.md
index 8546a8698..1f0ab5339 100644
--- a/docs/4.0/examples/index.md
+++ b/docs/4.0/examples/index.md
@@ -14,14 +14,14 @@ Examples that focus on implementing uses of built-in components provided by Boot
 <div class="row bd-examples">
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/starter-template/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/starter-template.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/starter-template.png" alt="" width="800" height="600">
       <h4>Starter template</h4>
     </a>
     <p>Nothing but the basics: compiled CSS and JavaScript.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/grid/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/grid.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/grid.png" alt="" width="800" height="600">
       <h4>Grids</h4>
     </a>
     <p>Multiple examples of grid layouts with all four tiers, nesting, and more.</p>
@@ -30,14 +30,14 @@ Examples that focus on implementing uses of built-in components provided by Boot
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/jumbotron/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/jumbotron.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/jumbotron.png" alt="" width="800" height="600">
       <h4>Jumbotron</h4>
     </a>
     <p>Build around the jumbotron with a navbar and some basic grid columns.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/narrow-jumbotron/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/jumbotron-narrow.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/jumbotron-narrow.png" alt="" width="800" height="600">
       <h4>Narrow jumbotron</h4>
     </a>
     <p>Build a more custom page by narrowing the default container and jumbotron.</p>
@@ -51,14 +51,14 @@ Taking the default navbar component and showing how it can be moved, placed, and
 <div class="row bd-examples">
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/navbars/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar.png" alt="" width="800" height="600">
       <h4>Navbar</h4>
     </a>
     <p>Super basic template that includes the navbar along with some additional content.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/navbar-top/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-static.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-static.png" alt="" width="800" height="600">
       <h4>Static top navbar</h4>
     </a>
     <p>Super basic template with a static top navbar along with some additional content.</p>
@@ -67,14 +67,14 @@ Taking the default navbar component and showing how it can be moved, placed, and
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/navbar-top-fixed/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-fixed.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-fixed.png" alt="" width="800" height="600">
       <h4>Fixed navbar</h4>
     </a>
     <p>Super basic template with a fixed top navbar along with some additional content.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/navbar-bottom/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-bottom.jpg" alt="">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/navbar-bottom.png" alt="">
       <h4>Bottom navbar</h4>
     </a>
     <p>Super basic template with a bottom navbar along with some additional content.</p>
@@ -88,14 +88,14 @@ Brand new components and templates to help folks quickly get started with Bootst
 <div class="row bd-examples">
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/album/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/album.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/album.png" alt="" width="800" height="600">
       <h4>Album</h4>
     </a>
     <p>Simple one-page template for photo galleries, portfolios, and more.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/cover/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/cover.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/cover.png" alt="" width="800" height="600">
       <h4>Cover</h4>
     </a>
     <p>A one-page template for building simple and beautiful home pages.</p>
@@ -104,14 +104,14 @@ Brand new components and templates to help folks quickly get started with Bootst
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/carousel/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/carousel.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/carousel.png" alt="" width="800" height="600">
       <h4>Carousel</h4>
     </a>
     <p>Customize the navbar and carousel, then add some new components.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/blog/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/blog.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/blog.png" alt="" width="800" height="600">
       <h4>Blog</h4>
     </a>
     <p>Simple two-column blog layout with custom navigation, header, and type.</p>
@@ -120,14 +120,14 @@ Brand new components and templates to help folks quickly get started with Bootst
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/dashboard/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/dashboard.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/dashboard.png" alt="" width="800" height="600">
       <h4>Dashboard</h4>
     </a>
     <p>Basic admin dashboard shell with fixed sidebar and navbar.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/signin/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sign-in.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sign-in.png" alt="" width="800" height="600">
       <h4>Sign-in page</h4>
     </a>
     <p>Custom form layout and design for a simple sign in form.</p>
@@ -136,14 +136,14 @@ Brand new components and templates to help folks quickly get started with Bootst
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/justified-nav/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/justified-nav.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/justified-nav.png" alt="" width="800" height="600">
       <h4>Justified nav</h4>
     </a>
     <p>Create a custom navbar with justified links. Heads up! Not too Safari friendly.</p>
   </div>
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/sticky-footer/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sticky-footer.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sticky-footer.png" alt="" width="800" height="600">
       <h4>Sticky footer</h4>
     </a>
     <p>Attach a footer to the bottom of the viewport when the content is shorter than it.</p>
@@ -152,7 +152,7 @@ Brand new components and templates to help folks quickly get started with Bootst
 
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/sticky-footer-navbar/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sticky-footer-navbar.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/sticky-footer-navbar.png" alt="" width="800" height="600">
       <h4>Sticky footer w/ navbar</h4>
     </a>
     <p>Attach a footer to the bottom of the viewport with a fixed top navbar.</p>
@@ -166,7 +166,7 @@ Examples that focus on future-friendly features or techniques.
 <div class="row bd-examples">
   <div class="col-6 col-md-4">
     <a href="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/offcanvas/">
-      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/offcanvas.jpg" alt="" width="800" height="600">
+      <img class="img-thumbnail" src="{{ site.baseurl }}/docs/{{ site.docs_version }}/examples/screenshots/offcanvas.png" alt="" width="800" height="600">
       <h4>Offcanvas</h4>
     </a>
     <p>Build a toggleable off-canvas navigation menu for use with Bootstrap.</p>
diff --git a/docs/4.0/examples/justified-nav/justified-nav.css b/docs/4.0/examples/justified-nav/justified-nav.css
index 0ca9aabb5..86c828190 100644
--- a/docs/4.0/examples/justified-nav/justified-nav.css
+++ b/docs/4.0/examples/justified-nav/justified-nav.css
@@ -20,7 +20,7 @@ body {
 }
 
 .navbar {
-  background-image: linear-gradient(to bottom, #f7f7f7 0%,#eee 100%);
+  background-image: linear-gradient(to bottom, #f7f7f7 0%, #eee 100%);
   border: 1px solid #e5e5e5;
 }
 
diff --git a/docs/4.0/examples/navbar-bottom/index.html b/docs/4.0/examples/navbar-bottom/index.html
index 3046f9b9b..675428c54 100644
--- a/docs/4.0/examples/navbar-bottom/index.html
+++ b/docs/4.0/examples/navbar-bottom/index.html
@@ -21,7 +21,7 @@
         <a class="btn btn-lg btn-primary" href="../../components/navbar/" role="button">View navbar docs &raquo;</a>
       </div>
     </div>
-    <nav class="navbar fixed-bottom navbar-expand navbar-dark bg-dark">
+    <nav class="navbar fixed-bottom navbar-expand-sm navbar-dark bg-dark">
       <a class="navbar-brand" href="#">Bottom navbar</a>
       <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarCollapse" aria-controls="navbarCollapse" aria-expanded="false" aria-label="Toggle navigation">
         <span class="navbar-toggler-icon"></span>
diff --git a/docs/4.0/examples/screenshots/album.jpg b/docs/4.0/examples/screenshots/album.jpg
deleted file mode 100644
index 127d9a97e..000000000
--- a/docs/4.0/examples/screenshots/album.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/album.png b/docs/4.0/examples/screenshots/album.png
new file mode 100644
index 000000000..bd876afb3
--- /dev/null
+++ b/docs/4.0/examples/screenshots/album.png
diff --git a/docs/4.0/examples/screenshots/blog.jpg b/docs/4.0/examples/screenshots/blog.jpg
deleted file mode 100644
index 54dd4eeed..000000000
--- a/docs/4.0/examples/screenshots/blog.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/blog.png b/docs/4.0/examples/screenshots/blog.png
new file mode 100644
index 000000000..84262009b
--- /dev/null
+++ b/docs/4.0/examples/screenshots/blog.png
diff --git a/docs/4.0/examples/screenshots/carousel.jpg b/docs/4.0/examples/screenshots/carousel.jpg
deleted file mode 100644
index 500863682..000000000
--- a/docs/4.0/examples/screenshots/carousel.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/carousel.png b/docs/4.0/examples/screenshots/carousel.png
new file mode 100644
index 000000000..2cb74fdbd
--- /dev/null
+++ b/docs/4.0/examples/screenshots/carousel.png
diff --git a/docs/4.0/examples/screenshots/cover.jpg b/docs/4.0/examples/screenshots/cover.jpg
deleted file mode 100644
index 0b22c0001..000000000
--- a/docs/4.0/examples/screenshots/cover.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/cover.png b/docs/4.0/examples/screenshots/cover.png
new file mode 100644
index 000000000..9b4b782ae
--- /dev/null
+++ b/docs/4.0/examples/screenshots/cover.png
diff --git a/docs/4.0/examples/screenshots/dashboard.jpg b/docs/4.0/examples/screenshots/dashboard.jpg
deleted file mode 100644
index 6595c049a..000000000
--- a/docs/4.0/examples/screenshots/dashboard.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/dashboard.png b/docs/4.0/examples/screenshots/dashboard.png
new file mode 100644
index 000000000..e573cae47
--- /dev/null
+++ b/docs/4.0/examples/screenshots/dashboard.png
diff --git a/docs/4.0/examples/screenshots/grid.jpg b/docs/4.0/examples/screenshots/grid.jpg
deleted file mode 100644
index ef624e866..000000000
--- a/docs/4.0/examples/screenshots/grid.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/grid.png b/docs/4.0/examples/screenshots/grid.png
new file mode 100644
index 000000000..47be687fe
--- /dev/null
+++ b/docs/4.0/examples/screenshots/grid.png
diff --git a/docs/4.0/examples/screenshots/jumbotron-narrow.jpg b/docs/4.0/examples/screenshots/jumbotron-narrow.jpg
deleted file mode 100644
index 3af127c0f..000000000
--- a/docs/4.0/examples/screenshots/jumbotron-narrow.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/jumbotron-narrow.png b/docs/4.0/examples/screenshots/jumbotron-narrow.png
new file mode 100644
index 000000000..474138834
--- /dev/null
+++ b/docs/4.0/examples/screenshots/jumbotron-narrow.png
diff --git a/docs/4.0/examples/screenshots/jumbotron.jpg b/docs/4.0/examples/screenshots/jumbotron.jpg
deleted file mode 100644
index aaf7f30e4..000000000
--- a/docs/4.0/examples/screenshots/jumbotron.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/jumbotron.png b/docs/4.0/examples/screenshots/jumbotron.png
new file mode 100644
index 000000000..80b71ba4b
--- /dev/null
+++ b/docs/4.0/examples/screenshots/jumbotron.png
diff --git a/docs/4.0/examples/screenshots/justified-nav.jpg b/docs/4.0/examples/screenshots/justified-nav.jpg
deleted file mode 100644
index 098bf6fb6..000000000
--- a/docs/4.0/examples/screenshots/justified-nav.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/justified-nav.png b/docs/4.0/examples/screenshots/justified-nav.png
new file mode 100644
index 000000000..86f215009
--- /dev/null
+++ b/docs/4.0/examples/screenshots/justified-nav.png
diff --git a/docs/4.0/examples/screenshots/navbar-bottom.jpg b/docs/4.0/examples/screenshots/navbar-bottom.jpg
deleted file mode 100644
index c25c2f89c..000000000
--- a/docs/4.0/examples/screenshots/navbar-bottom.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/navbar-bottom.png b/docs/4.0/examples/screenshots/navbar-bottom.png
new file mode 100644
index 000000000..7f4058033
--- /dev/null
+++ b/docs/4.0/examples/screenshots/navbar-bottom.png
diff --git a/docs/4.0/examples/screenshots/navbar-fixed.jpg b/docs/4.0/examples/screenshots/navbar-fixed.jpg
deleted file mode 100644
index 419bb7e50..000000000
--- a/docs/4.0/examples/screenshots/navbar-fixed.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/navbar-fixed.png b/docs/4.0/examples/screenshots/navbar-fixed.png
new file mode 100644
index 000000000..2b94339c6
--- /dev/null
+++ b/docs/4.0/examples/screenshots/navbar-fixed.png
diff --git a/docs/4.0/examples/screenshots/navbar-static.jpg b/docs/4.0/examples/screenshots/navbar-static.jpg
deleted file mode 100644
index 29f1643cc..000000000
--- a/docs/4.0/examples/screenshots/navbar-static.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/navbar-static.png b/docs/4.0/examples/screenshots/navbar-static.png
new file mode 100644
index 000000000..bdbb08573
--- /dev/null
+++ b/docs/4.0/examples/screenshots/navbar-static.png
diff --git a/docs/4.0/examples/screenshots/navbar.jpg b/docs/4.0/examples/screenshots/navbar.jpg
deleted file mode 100644
index b58877c08..000000000
--- a/docs/4.0/examples/screenshots/navbar.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/navbar.png b/docs/4.0/examples/screenshots/navbar.png
new file mode 100644
index 000000000..a9c4b67a5
--- /dev/null
+++ b/docs/4.0/examples/screenshots/navbar.png
diff --git a/docs/4.0/examples/screenshots/offcanvas.jpg b/docs/4.0/examples/screenshots/offcanvas.jpg
deleted file mode 100644
index 5bb3ca1f4..000000000
--- a/docs/4.0/examples/screenshots/offcanvas.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/offcanvas.png b/docs/4.0/examples/screenshots/offcanvas.png
new file mode 100644
index 000000000..c448d042a
--- /dev/null
+++ b/docs/4.0/examples/screenshots/offcanvas.png
diff --git a/docs/4.0/examples/screenshots/sign-in.jpg b/docs/4.0/examples/screenshots/sign-in.jpg
deleted file mode 100644
index e3309bdf6..000000000
--- a/docs/4.0/examples/screenshots/sign-in.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/sign-in.png b/docs/4.0/examples/screenshots/sign-in.png
new file mode 100644
index 000000000..23095f827
--- /dev/null
+++ b/docs/4.0/examples/screenshots/sign-in.png
diff --git a/docs/4.0/examples/screenshots/starter-template.jpg b/docs/4.0/examples/screenshots/starter-template.jpg
deleted file mode 100644
index ba99c7e4d..000000000
--- a/docs/4.0/examples/screenshots/starter-template.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/starter-template.png b/docs/4.0/examples/screenshots/starter-template.png
new file mode 100644
index 000000000..be6ea293d
--- /dev/null
+++ b/docs/4.0/examples/screenshots/starter-template.png
diff --git a/docs/4.0/examples/screenshots/sticky-footer-navbar.jpg b/docs/4.0/examples/screenshots/sticky-footer-navbar.jpg
deleted file mode 100644
index 05b7d8d21..000000000
--- a/docs/4.0/examples/screenshots/sticky-footer-navbar.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/sticky-footer-navbar.png b/docs/4.0/examples/screenshots/sticky-footer-navbar.png
new file mode 100644
index 000000000..fed9a2a8c
--- /dev/null
+++ b/docs/4.0/examples/screenshots/sticky-footer-navbar.png
diff --git a/docs/4.0/examples/screenshots/sticky-footer.jpg b/docs/4.0/examples/screenshots/sticky-footer.jpg
deleted file mode 100644
index b0914f532..000000000
--- a/docs/4.0/examples/screenshots/sticky-footer.jpg
+++ /dev/null
diff --git a/docs/4.0/examples/screenshots/sticky-footer.png b/docs/4.0/examples/screenshots/sticky-footer.png
new file mode 100644
index 000000000..98a6f3839
--- /dev/null
+++ b/docs/4.0/examples/screenshots/sticky-footer.png