i used to use snagit, the free version (i think it's out there on oldversion or somewhere like that). however, i now use gadwin systems printscreen.
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I've tried several of these apps in the past and tried a couple of new ones posted here. Snagit is still the best since you can add text and drawing annotations without leaving the app.
Why would you need more than that? It works on any computer I might use. You can edit the picture, add arrows etc in paint. If I get used to a program like snag it, I won't know what to do when I'm on another computer that doesn't have snag it.
Using print screen + paint is the equivalent of calling your broker and getting price updates as you draw your charts by hand. Sure, you could do it, by why would you want to when there's so much that makes your life easier?