Crash on open after editing resource pack

Put the summary of the bug you're having here

What I expected to happen was...:
The launcher to launch the game

What actually happened was...:
The launcher closed, The game opened for a split second then closed.

Steps to Reproduce:
1. I edited widgets.png and added it to a texture pack (I close the game and launcher when I update a pack that's in my folder. I'm still not sure if I have to)
2. I started the launcher
3. I hit "Play"