I have the same problem since the update to IOS X.
Get a message it's the wrong file extension, too, just like NW. It's a PNG file which even says before uploading it's an acceptable file extension...once I figure out what the problem is, I'll let everyone know.
To post the weeping angel, I had to edit it, put it in iCloud, go to my laptop, change the file extension to JPG, & upload from there. What a pain!!!
I WANT THE SKELECORN, TOO!!!
Now that I've put it out there, it'll never show up...lol
Got the angel & it's called Mourning Angel for the card, NW. Purely decor.