We have covered many screenshot tools for Windows 7 including the portable ones like ScreenCatch and PrtScr. RapiCapWin is another freeware tool which can capture screen in various formats and proportions. It presents you with three modes of capture, full screen, the active window and a rectangular area. The application is pretty simple and straightforward and also easy to use.
When you run the application, you can various options for capture including setting the format and image resolution, screen area etc. Once you capture the screen it provides you with options to open the image, the contained folder, send the image as email as well as delete the file.
The application comes in portable version as well enabling you to use it without having to install.