Display message if image object is too large for upload

[sdevalk]

Scenario: I want to upload a fairly large image object in the manage app (some 20 MB). However, if I click on the 'save' button nothing seems to be happening. But if I look at the dev console, both a 404 and a 413 are displayed - so I guess my image is too large. Would it be possible to handle this gracefully, e.g. by displaying a message to the user?