Using the contact form here or the plugin forum on wordpress.org some people mentioned that my Image Source Control plugin does fail on activation. This problem seems to happen only on bigger blogs with a couple of thousand posts and images. I finally found the time to fix this issue, but since it touches different part of the plugin, I want to explain a bit more in case you are facing any problems.
Auto-Index on installation
The cause of the problems on plugin activation is the auto indexing of images. To create the list of missing image sources I needed to query images without it. Unfortunately, WordPress didn’t provide a way to do this for images without any image source, but only for those with an empty image source. Or as WordPress developers might say: there was no way of checking if a meta value was not existing, only if the ones existing were empty.
Anyway, this changed in WordPress 3.5, but since ISC worked there was no reason to change the plugins code. When more and more big blogs are using Image Source Control, more and more of them reported the same issue.
Practically, the only visible changes for users are the now existing two lists of missing images. One for images with an empty source string (normally images added after installing ISC) and one for images with no source information at all (images added prior to ISC installation).
Still, I also checked some other functions and changed a bit here and there. Despite my tests there might be some issues. Maybe images with sources are still listed in the missing image source or not listed in the source list in the frontend (when using the isc_list function or shortcode). Please report back in both cases.
Issues with embedded sources
There is no rest after solving one big issue. Some people are reporting that the source is not visible on the images. I might say this highly depends on the theme they are using, but there is probably another, better solution anyway. I am not sure how to fix this yet and would appreciate some suggestions and help.
Anyway, keep me posted if you run into this issue so I can gather more information about it.