I upgraded our install from 1.5.3 to 2.1.2 as per the subject, and now I am finding that image uploads (themes, collection, etc. - any image upload) are not working. That is, I receive an Omeka error and nothing occurs. Permissions are 775, the correct .htdocs file was uploaded. I have seen something on the forums about servers possibly blocking the proc_open() function, but I have no idea how to determine if that is our issue, or what it could be. Is that an apache config setting?