Played around for a bit with a photo editor called Lunapic. They have an option that allows you to turn digital photos into coloring pages. They also do a lousy job with most of them by leaving out a lot of details. The fewer objects you have in the picture and with more contrast, the better it does. 

Anyway, I would write more but I’m getting pretty tired. I’m going to watch my show, read a chapter in my book, and then crash.