I’m currently working on an ASCIIcast, containing a small tutorial introducing ImageMagick v7.0.x
This is still work-in-progress. I make no promises when it will be ready. If you want to get some ideas about the power of ImageMagick (or if you want to learn things about it which you didn’t know so far), go to my collected StackOverflow answers from the past few years and have a look at these: