ICAC Task Force recently opened an investigation into 18 CSAM files being shared online. Further investigation revealed that the sharer was actually offering 134 CSAM videos, and police claim they were able to trace those files to the account of local resident and well-known cartoonist Darrin Bell.
Its a messy subject but any kind of sharing/selling quickly evaporates any reservation I have on prosecuting. It's still child porn and, even without any "real" victims, trying to build a community around it is gross.
The part about using the images to groom children is also an angle I had never really thought about.