You can do it. There are a set of steps. But for starters, let's eliminate the situation when it comes to works of unknown authorship, without signatures, as well as paintings by amateur artists, amateur copies and mass reproductions. All of them often cost symbolic money, 1,000-5,000 rubles. The age of the picture (old — not old) is also not a criterion for its price. So we take it as a condition that the name of the author of the evaluated work is known in advance and the picture is signed. Then the general procedure will be something like this: