It's pretty obvious from the description. The lock screen is just a program running on the phone, as is the launcher that displays the home screen. If those pro

It's pretty obvious from the description. The lock screen is just a program running on the phone, as is the launcher that displays the home screen. If those programs crash, you won't be able to do very much with the phone. Apparently images with uncommon features (such as color profiles), or images that are malformed, can cause an error condition that causes both of these applications to exit or crash. Since displaying the background image is not critical to the operation of these programs, any failures in loading or displaying that image should have been caught and handled in such a way that the program doesn't crash. It should simply display a solid color background instead. Depending on the language used to implement these programs, that might be more or less engineering effort.