webform_screenshot.png missing - breaks Apps

The webform_screenshot.png file is missing from LevelTen's appserver, as seen in the broken image at http://apps.leveltendesign.com/app/webform; this ultimately causes Apps as included with OpenEnterprise to break, resulting in:

PDOException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'public://apps/webform_screenshot_0.png' for key 'uri': UPDATE {file_managed} SET uid=:db_update_placeholder_0, filename=:db_update_placeholder_1, uri=:db_update_placeholder_2, filemime=:db_update_placeholder_3, filesize=:db_update_placeholder_4, status=:db_update_placeholder_5, timestamp=:db_update_placeholder_6, type=:db_update_placeholder_7, uuid=:db_update_placeholder_8 WHERE (fid = :db_condition_placeholder_0) ; Array ( [:db_update_placeholder_0] => 1 [:db_update_placeholder_1] => webform_screenshot.png [:db_update_placeholder_2] => public://apps/webform_screenshot_0.png [:db_update_placeholder_3] => image/png [:db_update_placeholder_4] => 7390 [:db_update_placeholder_5] => 1 [:db_update_placeholder_6] => 1360091058 [:db_update_placeholder_7] => image [:db_update_placeholder_8] => 0cbd5ba5-6c19-c174-593d-78236a31279c [:db_condition_placeholder_0] => 4123 ) in drupal_write_record() (line 7106 of /data/www/includes/common.inc).

And also you get an extra ".png" file (which actually contains an HTML "page not found" page) created every time you go to the Apps tab (we had over 4000 of them, built up over time).

To temporarily work around this, you can:

• Remove all sites/default/files/apps/webform_screenshot* files.
• Run delete from file_managed where filename like 'webform_screenshot%'; in mysql (eg. drush sql-cli).
• Clear all caches.

That will download a fresh HTML page not found message, save it as webform_screenshot.png, and will allow you to access the Apps page ... until you clear the cache again, then you're back to an error message.

A quick fix would of course be to post the screenshot image. A better solution would be to make it handle it properly when a screenshot is missing.