morbidatdd

Started having the exact issue. Was working fine on Saturday, but this morning started having the same issues as you. Checked plugins, but the last one modified\updated was on Friday.

When I view source, I am seeing POST /wp-admin/admin-ajax.php
500 Internal Server Error errors generated as the screen that should display media stays blank and in a constant state of loading. If I try to upload, WordPress reports HTTP Error. I verified that the file permissions for my uploads directory is correct.

However, I can access my media library with no issues, yet still get the HTTP Error when uploading. TO make things even stranger, even though I get the error, the image does show up in my media library.

The author has not been active on this plugin or his personal blog since March. I hope that he is still around to get this compatible with 2.8, or that someone else takes a stab at figuring out where the issue is. This is one of my favorite plugins and also quit working entirely after upgrading WP from 2.7.