You're wanting to convert GIF to JPG? Well, first off, if it's an animated gif, you CAN open in Photoshop but only the first frame and when you re save-as, you'll lose the rest. Gifs can also be opened/resized in ImageReady [hitting CTRL+SHIFT+M in PS opens IR]. So simply open the GIF photoshop] and immediately go BACK to File >> Save as.. and choose .JPEG from the drop-down menu. Select your quality [1-12]and hit enter!
If you're wanting to post images HERE, simply upload somewhere else [personal web space?] and use the bb codes to insert.
Example [ img ] full web address here [ / i m g ] [WITHOUT SPACES] should produce an image in it's place.
Erm... I hope this answers you.