Preconditions:

Image assets repository should be empty. Default: Media/Images

Steps:

1. Create Content Type with image assets field type
2. Go to Content/Content structure and click Create
3. Select CT from step 1
4. Click Select from your repository button

Actual result:

UDW is displayed, user can see it empty, there is no message at all - see attachment, please.

Expected result:

Information message like on empty bookmarks tab could be displayed (attachment).

Or if we are in a perfect world Select from your repository button could be disabled if repository is empty