Poor screenshot quality, what to do?

Question

Screenshots

In general, when I take a screenshot through PrintScreen and paste it there, for example, in VK, Photoshop, etc. It has poor quality. Even when I take a screenshot in the game (Game samp, screenshot with F8), the quality is also poor. But as soon as I took a screenshot from PrintScreen and inserted it into the built-in program "Scissors", and then saved it in PNG. That quality is normal. I use Windows 7 PRO.