I want to create a gallery that shows full size images at the album page.
Ie, I don't want to click thumbnails to get to a specific image.php page. The images should be viewable full size from album.php.
getFullImageURL doesn't seem to work for this. Am I wrong?

Do you want to open the image in a colorbox or show the full image instead of thumbs? The first has been answered lots of times (search for lightbox or similar). FullimageURL is the right function but as told on your other thread it does not "print" anything. In any case you have to modifiy your theme so now is the right time to read the theming tutorial to learn the basics.

And the post does not show up at first because the first posts of new users are moderated (you have been informed about that on registration).