Direct Tumblr uploads not posting the original image

Something that got my attention was how Danbooru fetches the full sized image from Tumblr. I tried to upload this particular image through direct link and it gave me post #2636973, a JPEG with the same dimensions as the original. However, if you look at the original link itself on Tumblr, you'll notice that it's actually a 2 MB PNG that I had to download and post via the file upload process, giving me post #2636975. Anyone else have this problem?

Weird. In my case, I can't use bookmarklet on the Tumblr post link (it will end up with a blank page on the upload page). That's why I always upload through *.media.tumblr.com to ensure that I got the highest resolution and size available.

If you open the image link into a new tab from the post page and then use the Bookmarklet, it should get the correct image size as well as use the post page for the source.... at least, that's been my experience...