I just worked through a random bug with the ImageGallery module. I'm not exactly sure what version it is, but it's a recent one. This may help someone else.
The bug appears when your in the admin backend, then clicking on an image in the "Photos" tab, then trying to rotate the image.
It looks like the bug only happens when you don't have your ss installation in the root dir, and therefore using .htaccess to reroute urls.
Firebug returns a 500 error like so:
ERROR [Warning]: copy(/Users/username/Clients/clientname/ss//domain.co.nz/ss/assets/image-gallery/Gallery/default-gallery/_resampled/rotateclockwise-016.jpg): failed to open stream: No such file or directory IN GET /domain.co.nz/ss/ImageGalleryManager_Controller/rotateimage/24/cw?flush=1 Line 206 in /Users/username/Clients/client/htdocs/ss/image_gallery/code/ImageGalleryManager.php
I edited the working directory to hide client info etc.
To fix I edited the rotateimage() function in ImageGalleryManager.php & changed the line:
$url = $this->urlParams['OtherID'] == 'cw' ? $image->RotateClockwise()->URL : $image->RotateCounterClockwise()->URL;
$url = $this->urlParams['OtherID'] == 'cw' ? $image->RotateClockwise()->Filename : $image->RotateCounterClockwise()->Filename;
This way the code only worries about the dir path from the root of the install, rather than the url etc.