Astronomy Picture of the Day
You can go down to the Archive and see each days posting, or the Index to see different categories of pics. Just browse through it, there are so many amazing pics of our universe.
And sorry about the picture, in point of fact, I was too lazy to reduce it, plus that galaxy is huge so I thought perspective might help ;-)
To get a screenshot, hit the PrintScreen button, then open up the Microsoft Paint program (Start>All Programs>Accessories Paint should be in the list.)
You should then be able to click on the screen and then just hit Ctrl+V to paste in into the screen. Now go up to File>Save As and then save it as a jpeg.
Then you can upload it to your account (if this site lets you host pictures, I have no idea?) or one of those photobucket sites and then link the image.
Hope that was what you were looking for Sno.