User blog comment:YoshiMario2/How do i make a screenshot on terraria?/@comment-24006028-20131127162253

Printscreen does the job, then to copy it into paint or onto a site like Imgur.com. If you use Dropbox, you can turn on the option to copy them automatically into a folder.

If you are using steam, I believe the button you need to press is F12 to make a screenshot. It will be automatically placed under a tab when you 'Shift Tab' out.