I admit I have never handled a child porn case, I do corporate law and contract law. But I have sat in the court room watching child porn cases and they use EVERYTHING they can to fry the person and paint them as a pedophile. I remember one guy was on trial for taking pictures of girls at a state fair, he would zoom in on their butts, fully clothed, but they charged him with possession and production. During the case, they brought up that they found a DVD movie called Wanda Nevada, staring a young Brooke Shield (not the Pretty Baby movie, thank God)to use this against him. They described the movie as a pedophile man who wins a 12 year old girl in a card game and abducts her. The judge and onlookers all gasped as if simply having that movie is proof positive the guy is a pedophile. That's what they do. They search everything you have on your computer and in your home and they'll use every single little thing they can to bolster their case.
It's highly irresponsible for you to come on here and tell people that collecting these types of pictures is legal and they have nothing to worry about. Bullshit. Not only are many of the pictures technically legal but they'll even use the legal ones against you!
For God's sake people, take precautions, be paranoid. Don't listen to some armchair lawyer when it comes to your freedom.
There are people far smarter than I am about hiding your tracks and your collection. Take their advice. But start with using a full-time VPN that is not based in a country subject to the U.S. Patriot Act AND fully encrypting your entire desktop computer and external hard drives with VeraCrypt, also get a Keylogger encryption system. (there are other posts regarding security that can walk you through this all step by step).
I would also add that people should go through their entire house and belongings and remove anything that even remotely indicates you have an interest in young girls. Even legal, mainstream movies. Get rid of it all. Copy it digitally and encrypt it.
Don't listen to clods on here telling you that a 10 year old girl in garter belts, stockings, heels, and a g string spreading her legs and licking a lolipop looking suggestively into the camera is legal.
I don't care about some debate with some anonymous person on the internet with no formal education in the law, what I care about is that people don't get lulled into a sense of complacency and get that life-changing, dreaded knock on their door at 5 o'clock in the morning.