Just looked at the designs, and have a few suggestions. Perhaps to be considered as alternatives in A/B testing. In no particular order.
- Right now it doesn't specify what "This image" is. There can be multiple on the page and in the background. Showing it as a thumbnail inside the dialog would be helpful (I wouldn't suggest using the MediaWiki-Filename though)
- All dialogs have a blue title in the topbar. Is this a link ? Otherwise making it black would make more sense (like the rest of the Vector skin)
- The logged-out warning looks like an error. Not sure if that is a good thing. The only other place where anonymous users are addresses specifically is on the edit page where there is a sudle notice regarding the IP-address being saved (on most wikis the text for this notice is in a small box containing the text in a small non-bold font. With a blue "I"-information icon or a lightbulb next to it). But the error-style seems disturbing for that message.
- I like the layout for the main "Filter settings'-dialog, but the layout of the "This image"-dialog is a bit confusing to me. It's triggered through the image link, but the title of the dialog is the same as the dialog for the main "Filter settings". I'd like to try making the two different dialogs more distinguishable. For example: Move the title "This image matches the following filters" up to where it says "Content Filter Settings", and hiding the "Additional Content Filters"-section. Perhaps include a link back to the overall display settings to make up for the absence of that section, although I think it's absence is fine.