How do you change the main image of a page?

Sorry for noobing out but can someone please explain how change the main image that appears on the front of a page? I want ti change it to a different image that is already uploaded in the gallery.

I don't think you can, I think a mod has to do it.

oh really? :/ that stinks. ok well thanks for the help.

yea, beacuse some main images are pretty lame, unless you can change the main image when you have over 1000 points which would be fine

I think it should be by thumbs up/thumbs down rating. So if you view all images, the most thumbs up gets displayed on the main page.

"I think it should be by thumbs up/thumbs down rating. So if you view all images, the most thumbs up gets displayed on the main page.
"