My game crashes when i go to configure realms

The game can run regualr worlds and servers. i can double click my realm and it will load. the issue is i want to swap over to world 2. when i hit configure realm it loads for a couple seconds then it says "Saving world" then crashes. I am the owner of this realm as well. 

( The game crashed whilst rendering screen
Error: java.lang.NullPointerException: Cannot invoke "java.awt.image.BufferedImage.getWidth()" because "☃" is null
Exit Code: -1 )