You need to first rightclick that screenshot in its folder and copy it to your "Pictures" folder. Then you need to go to an image sharing site like Photobucket and upload it there. Then you need to get the url to the image and paste it between the [IMG] tags to post it.
O_o huh...
You need to first rightclick
Ookay then..? Edit: I don't
Edit: I don't want to sound rude, but please, either you fix the image or delete it. :/ It's only taking up space.