Pantech

I got my Pantech Crux about a week ago. If I take a picture with it the picture fills the screen and is the same size as the default pictures (like the forest) when I use it for wallpaper. But if I put a picture on the micro SD card I can't get it to look any bigger than a thumbnail. I tried changing the pixel size to match the others using Corel but I still can't get it to look any bigger. Any ideas?????
I found a comment on another site from a guy who said he figured it out but he didn't give any details and then said he returned the phone. Since it wasn't a forum I couldn't ask there. I'd sure like any help anyone can give.
Thanks