diff --git a/curriculum/challenges/english/01-responsive-web-design/applied-accessibility/improve-accessibility-of-audio-content-with-the-audio-element.md b/curriculum/challenges/english/01-responsive-web-design/applied-accessibility/improve-accessibility-of-audio-content-with-the-audio-element.md
index fa69314f96f..2a29cafcb43 100644
--- a/curriculum/challenges/english/01-responsive-web-design/applied-accessibility/improve-accessibility-of-audio-content-with-the-audio-element.md
+++ b/curriculum/challenges/english/01-responsive-web-design/applied-accessibility/improve-accessibility-of-audio-content-with-the-audio-element.md
@@ -26,7 +26,7 @@ Here's an example:
 
 # --instructions--
 
-Time to take a break from Camper Cat and meet fellow camper Zersiax (@zersiax), a champion of accessibility and a screen reader user. To hear a clip of his screen reader in action, add an `audio` element after the `p` element. Include the `controls` attribute. Then place a `source` element inside the `audio` tags with the `src` attribute set to `https://s3.amazonaws.com/freecodecamp/screen-reader.mp3` and `type` attribute set to `"audio/mpeg"`.
+Time to take a break from Camper Cat and meet fellow camper Zersiax (@zersiax), a champion of accessibility and a screen reader user. To hear a clip of his screen reader in action, add an `audio` element after the `p` element. Include the `controls` attribute. Then place a `source` element inside the `audio` tags with the `src` attribute set to `https://cdn.freecodecamp.org/curriculum/applied-accessibility/screen-reader.mp3` and `type` attribute set to `"audio/mpeg"`.
 
 **Note:** The audio clip may sound fast and be difficult to understand, but that is a normal speed for screen reader users.
 
@@ -70,7 +70,7 @@ The value for the `src` attribute on the `source` tag should match the link in t
 ```js
 assert(
   $('source').attr('src') ===
-    'https://s3.amazonaws.com/freecodecamp/screen-reader.mp3'
+    'https://cdn.freecodecamp.org/curriculum/applied-accessibility/screen-reader.mp3'
 );
 ```
 
@@ -108,7 +108,7 @@ assert($('source').attr('type') === 'audio/mpeg');
   <main>
     <p>A sound clip of Zersiax's screen reader in action.</p>
     <audio controls>
-      <source src="https://s3.amazonaws.com/freecodecamp/screen-reader.mp3" type="audio/mpeg"/>
+      <source src="https://cdn.freecodecamp.org/curriculum/applied-accessibility/screen-reader.mp3" type="audio/mpeg"/>
     </audio>
   </main>
 </body>
diff --git a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-a-column-in-the-tweet-embed.md b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-a-column-in-the-tweet-embed.md
index ae884b649af..b1d8e41d077 100644
--- a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-a-column-in-the-tweet-embed.md
+++ b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-a-column-in-the-tweet-embed.md
@@ -93,7 +93,7 @@ assert($('.profile-name').css('flex-direction') == 'column');
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
@@ -186,7 +186,7 @@ assert($('.profile-name').css('flex-direction') == 'column');
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
diff --git a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-rows-in-the-tweet-embed.md b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-rows-in-the-tweet-embed.md
index 8458c968c3d..3d6caeaf7d3 100644
--- a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-rows-in-the-tweet-embed.md
+++ b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/apply-the-flex-direction-property-to-create-rows-in-the-tweet-embed.md
@@ -102,7 +102,7 @@ assert(code.match(/footer\s*?{[^}]*?flex-direction:\s*?row;/g));
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
@@ -198,7 +198,7 @@ assert(code.match(/footer\s*?{[^}]*?flex-direction:\s*?row;/g));
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
diff --git a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-align-items-property-in-the-tweet-embed.md b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-align-items-property-in-the-tweet-embed.md
index 98b3d28d957..eedcad6beb0 100644
--- a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-align-items-property-in-the-tweet-embed.md
+++ b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-align-items-property-in-the-tweet-embed.md
@@ -95,7 +95,7 @@ assert($('.follow-btn').css('align-items') == 'center');
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
@@ -190,7 +190,7 @@ assert($('.follow-btn').css('align-items') == 'center');
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
diff --git a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-justify-content-property-in-the-tweet-embed.md b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-justify-content-property-in-the-tweet-embed.md
index 367ec16ba62..1dca1dac1cf 100644
--- a/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-justify-content-property-in-the-tweet-embed.md
+++ b/curriculum/challenges/english/01-responsive-web-design/css-flexbox/use-the-justify-content-property-in-the-tweet-embed.md
@@ -98,7 +98,7 @@ assert(
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>
@@ -192,7 +192,7 @@ assert(
   }
 </style>
 <header>
-  <img src="https://freecodecamp.s3.amazonaws.com/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
+  <img src="https://cdn.freecodecamp.org/curriculum/legacy-css-flexbox/quincy-twitter-photo.jpg" alt="Quincy Larson's profile picture" class="profile-thumbnail">
   <div class="profile-name">
     <h3>Quincy Larson</h3>
     <h4>@ossia</h4>