I'm trying to make photos that work to the size of the Facebook album covers. I've found lots of info on the old photo size, but I can't find anything in the APIs or information sheets that lets me know either the size or the aspect ratio. Any ideas?
Assuming that the album covers that you're asking about are FB Timeline covers, the image dimensions are 851px by 315px according to information on this page. The same information can be found at this Time Techland article.
Facebook has posted some information as well on this help page. The detailed specs include:
If you're looking for the size of pictures in the photo album, this site provides this spec:
The photo album cover would be governed by the same limitations, since from my understanding the cover image is just one of the images in the album.