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.

including the skin file in case of it being any relevance.

I will try update of java as I'm not sure I'm up to date and then report back