Problem uploading attachments

I suspect I have reached my quota for attachments - ~18 MB? as I am unable to upload additional attachments. There have been many attachments that I've "unattached" from the post they were intended for, and I'd love to delete those, but I don't see any way to do so.

The specific message I'm getting is:

Quote:

Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 25839729 bytes) in /home/papermod/public_html/forum/includes/class_image.php on line 2390

That's 128 MB, though, so surely my 18 MB isn't exceeding that limit... what else could be wrong? The problem exists when attempting to upload from multiple computers on multiple networks.

Thanks in advance.