I've been getting this question a lot, so I'll answer it here. The reason the image galleries for certain characters are locked is due to certain characters galleries being over sized. In turn, without a new format implemented to subdivide the pages, it would cause lagging on loading the image gallery pages.
This wasn't helped at all, by a previous user deciding to upload all of the manga pages available without editing the pictures first. I'm still debating what to do with that, considering some of the galleries are still to big.
Also, as I made it previous clear, some users tried to help with the renaming process of previous incorrect photos. Will I do appreciate the sentiment, they ended up causing more work for me in the long run. Their process of renaming photos involved creating duplicate photos which required me to delete the original afterwards. Honestly, I find that even more tedious to keep track of since we already have over 9k photos to manage.
Yup, anyone can still add photos to the synopsis. Just make sure it's relevant for the character, give it a short and sweet name for the photo, and limit yourself to 3-4 photos for each volume summary.