Doc: Update Image Viewer snapshot and add icons to instructions

Arranged the feature list according to the order of icons on the
toolbar and added icons.

Edited some text.

Task-number: QTCREATORBUG-27876
Change-Id: I4357329fbc137ea39b87e3630de507981d1611e5
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

doc/qtcreator/src/user-interface/creator-ui.qdoc

@@ -196,26 +196,26 @@
 
     \image qtcreator-image-viewer.png "Image viewer"
 
-    Use the toolbar buttons (1) or \l{Keyboard Shortcuts}{keyboard shortcuts}
-    to:
+    Use the toolbar buttons or \l{Keyboard Shortcuts}{keyboard shortcuts} to:
 
     \list
-
-        \li Export SVG images to pixmaps
-
-        \li Copy an image as a data URL, which enables you to include it in web
-            pages as if it were an external resource
-
-        \li Switch between background and outline modes
-
-        \li Zoom in and out
-
-        \li Fit images to screen
-
-        \li Return to original size
-
-        \li Play and pause animated GIF and MNG images
-
+        \li \inlineimage icons/export.png
+            - Export SVG images to pixmaps or copy an image as a data URL, which
+            enables you to include it in web pages as if it were an external
+            resource
+        \li \inlineimage icons/original-size.png
+            - Return images to their original size
+        \li \inlineimage icons/zoom-in.png
+            - Zoom in and out (\inlineimage icons/zoom-out.png
+            )
+        \li \inlineimage icons/run_small.png
+            - Play and pause animated GIF and MNG images
+        \li \inlineimage icons/qtcreator-desktopdevice-button.png
+            - Show and hide the image background
+        \li \inlineimage icons/switch-outline.png
+            - Show and hide the image outline
+        \li \inlineimage icons/fittoview.png
+            - Fit images to screen
     \endlist
 
     Select \uicontrol {Set as Default} to use the current settings for the