postlimit.com may help?
I’m entirely willing to be wrong, but I think postlimit.com only tells you how many total posts you’ve made? Which includes text posts and reblogs, rather than how many photos I can still upload. (I’m not entirely sure but I think some photos count as more, if the file size is bigger, rather than just simply, “You can upload xxx number of photos.”? But don’t quote me on that, it’s just a sense I get.)
I like to have the last dozen or so posts I do before ending the night to be Sailor Moon-related, since I do consider that my primary fandom here, but it’s hard to do that when I don’t know how close I’m getting to my limit and find myself suddenly out before I even realize it. ;__;