Your Screenshot-posting for beginners post needs some correction.
It states that “You should get a specialized program to take screenshots because it is much more flexible than the built-in Windows " PrtScn " request that only allows you to take a picture of the entire screen (or “Alt+PrtScn” to capture the active window) and by default uses an inferior file-format , BMP.”
Actually, the captured content is sent to the Windows clipboard, from where it can be pasted into an image editor and then saved to any supported image format besides BMP. For instance, I use IrfanView to save my screen captures to the JPG format.
As to FastStone Capture, one can find its last freeware version, which can be used as a portable app, at the homonymous site Last Freeware Version - FastStone Capture.