The criminal cases of copyright infringement are not common because most times a settlement is done prior to the filings. The cases that involve hard copies being taken are not infringement but common theft and those are prosecuted much more frequently. Taking a digital file of a photograph that has the possibility of selling for a large sum of money is no different than taking an oil painting from a store or museum.
You will hear terms like notice of action, Lis Pendens (real estate mostly) and legal notices. The important ones for those of you contemplating legal criminal action are more in the line of accessory after the fact, accessory before the fact and accessory to the crime. Basically it means others that helped with the theft and infringement are just as guilty as the person who committed the crime. Then there are the others that may apply like aiding and abetting, which includes giving aid and comfort, money, place to stay, harboring stolen property and things like that. The punishment is normally half the amount of the allowable charges.
I suggest you discuss this with an attorney or the local police or prosecutor to see if you want to really do this. I know that none of us want to do that but it may be the only way you get your property back. The sad part is for some is that if it is just one item or maybe two the cost to hire an attorney would probably be more than you can get. However with images it is different if there are DMCA issues.
The threat of criminal charges like criminal misconduct is serious and in most cases will have the person who might get charged wanting to get out of it. Seems really funny to me that the people who actually committed the infringement and theft also like to bring in others to share the blame. A simple act of returning the files and paying a fee could have kept theside line people out of hard times.
The references to harboring a felon or criminal has 4 tests for it under federal law so I would check those out more but I am not discussing them here.
The issue of fines keeps coming up so here it is again. The fines are for the government not you. You can collect damages but only in a civil court. As stated before, I think the civil should be filed first.
I am not an attorney. These are my person opinions and general information. These are not legal advice and should not be used as such.