There was a case (Knox?) where all he had were videos of close-up shots of girls' crotches, and that was defined as CP. I think it was filmed at a pool or something. Essentially, it's thought-crime.
The vague definition is a problem, but I don't think any portion of CP should be illegal unless it was actually abusive, coerced, etc.
There are only a few developed countries where simple possession is still legal.