Not punishable if the use of other people's pictures?

[Petr2801]

Good time ! =) I'm trying to resolve the issue.
Online you can dig up a bunch of different portals with pictures for your desktop. These wallpapers are in the public domain. I can upload any number of formats. Suppose I want to open a small shop and do a site that store. then take some of these oboin , bar, cut out a piece , say the horizon, and pour to your web site .
Whether such action is a violation of copyright? The idea is the image in the public domain is and I take only a piece of the whole picture. I just extract profits from the pictures (ieis, I do not sell the picture .) Have a right to make a claim for it ? If so, who? Will it be a violation of the law ?
Thanks in advance if anyone can help to understand this