Board Thread:Support Requests - Getting Technical/@comment-25463843-20160106182357/@comment-25463843-20160106185252

"Thanks for contacting Wikia. This is due to the size of the images. 5,388 × 7,300 pixels is a very high quality image. You would have to size the images down to below 5,000x5,000 (a rough maximum size on Wikia) in order for the thumbnailer to handle the image correctly."