404 on a missing resource /images/icons/view_16.png on the edit restrictions page

Monitor your web browser traffic with Fiddler2 from Microsoft. Install it while your browsers are closed.
Configure it to not hide the image requests. (in the rules menu)
Make sure that your browser uses Fiddler as its proxy. (tools/monitor with Fiddler for FF or tools/fiddler2 for IE)

Open a page
Edit it
Click on EDIT Restrictions (you may need to be admin)
Fiddler shows the missing file image and shows a 404. (see attachment)

All the 404 are alerts that I need to investigate to see where the error comes from.
There should be none.

2.9.3 has these resources
images\icons\view_16.png
images\icons\view_20.png
images\icons\view_20.gif

3.4.3 has these ones
images\icons\view_16-ie6.png
images\icons\view_20.png
images\icons\view_20.gif

So obviously the image cannot be found. As you can see on the attached image, the edit icon is present but not the view one.

Testing for missing resources should be standard.
You could have your testers and developers making sure with Fiddler like I do that no web request results in a 404 or similar error.