Organizing screenshot assets for the block tutorial inside the design…

…ers-developers directory in the repo (#12745)

docs/designers-developers/developers/tutorials/block-tutorial/block-controls-toolbars-and-inspector.md

@@ -4,7 +4,7 @@ To simplify block customization and ensure a consistent experience for users, th
 
 ## Toolbar
 
-<img src="https://cldup.com/jUslj672CK.png" width="391" height="79" alt="toolbar">
+![Screenshot of the rich text toolbar applied to a paragraph block inside the block editor](https://raw.githubusercontent.com/WordPress/gutenberg/master/docs/designers-developers/assets/toolbar-text.png)
 
 When the user selects a block, a number of control buttons may be shown in a toolbar above the selected block. Some of these block-level controls are included automatically if the editor is able to transform the block to another type, or if the focused element is an RichText component.
 
@@ -171,7 +171,7 @@ Note that `BlockControls` is only visible when the block is currently selected a
 
 ## Inspector
 
-<img src="https://github.com/WordPress/gutenberg/master/docs/designers-developers/developers/tutorials/block-tutorial/inspector.png" with="281" height="527" alt="inspector">
+![Screenshot of the inspector panel focused on the settings for a paragraph block](https://github.com/WordPress/gutenberg/master/docs/designers-developers/assets/inspector.png)
 
 The inspector is used to display less-often-used settings or settings that require more screen space. The inspector should be used for **block-level settings only**.