Are you on a shared hosting box? If so, this indicates that you've run out of memory when trying to process an image you uploaded into Garage. Usually, on a shared box, you can specify a custom php.ini for your directories to run with. You would want to tweak the following:
- memory_limit
- upload_max_filesize (optional)
- max_execution_time (optional)
Since all hosting companies offer different ways to handle this be sure to check with them before doing anything. For memory_limit most hosts have this set as small as 8M. I would recommend at least 32M or more if your host will support it.
Mark