Have a look at this video: This no longer works in Chrome or Firefox but it does in Safari. So, my advice is to find out as much as you can before getting into any endeavor and don't just trust the screenshots. In other words, do your due diligence.
You'll never get to know if the screenshots/ pics are real or not unless you see them in real. You just need to be very careful while signing-up for any any such money making program, from my own experience only 2 - 3 percent program are for real and rest are just fraud. But you can always search for reviews
You cannot be sure of any such results. The only way to be sure about a business' earnings are with a real financial audit by a professional auditor. Everything else can be faked and often is.
I see screenshots all the time on flippa for example, if someone were to buy something from there - would they be better to show a video of their stats rather than screenshots?