Sure thing, Anon!
So, basically, tumblr changed the original dashboard. They took away the bar at the top of your dash that allows you to make posts, have the home bar stick to the top of your dash as you scroll, and, most significantly, they changed post size. When you post gifs or graphics or pictures, the size has always been 500px. I’ve only been on Tumblr for about two years, but apparently, the 500px size post is way older than that.
By changing the post size from 500px to 540px today, tumblr essentially fucked up every picture and gif and edit on their site. They did this really insensitive, stupid thing, because every use is pissed. And rightly so. I’v only just started making gifs and I’ve made graphics in the past, and that shit takes serious time. To have your gifs be either distorted or fuzzy or cut off seriously sucks. It feels almost disrespectful because clearly the staff doesn’t really give a shit about us as users. I seriously doubt anybody would’ve wanted a larger post size had there been a poll.
The other thing about the update is that apparently, you can’t even make gifs that are 540px and have them not be distorted. Tumblr turns your gif/graphic into 500px from 540px and then distorts the image back. Either way, you get shitty-looking work.
Thankfully, the xkit guy is working really hard on fixing everything for us (bless him), and there’s another extension floating around that allows you to keep post size at 500px. Even with that, though, everyone needs to go email staff because if you have the extension your stuff will look good, but it won’t for anyone who doesn’t.
Hope that answers your question :)