custom skin causes app to crash

after migrating my account got the windows 10 beta version and my skin defaulted to "alex" I wanted to go back to my original since god knows when so clicked on custom skin and added the .png file of my old skin I found and downloaded from minecraft-skin-viewer.com. When I did this the app ended abruptly at that point. Now when I load it up its fine until I click on skins or the image (of what now shows me as steve) and my skin is the "steve" default one.