Yeah, and in this case I'm coming from page 1 and it's linking to page 2. My "Thumbnails per page" option is also set to 12, and everything works fine until I add a sub album.
Example: I go to page 1 of an album, eg http://domain.tld/new-album-1. I click on an image thumbnail. On the image.php page my getAlbumLinkURL() links to http://domain.tld/new-album-1/page/2 instead, even though the image is not on page 2.
If I remove the 12 in next_image(false, 12) in the album.php, page 1 only has the sub albums on it, the images then start on page 2. This then matches with what getAlbumLinkURL() is doing.
So, the ,12 seems to make a "pretend" page 1 for the images. The gallery system still thinks the images start on page 2. I need to correct whatever the underlying reason is for the images starting on page 2.
Unfortunately due to the layout, normalizeColumns() is not any use to me, but thanks for the suggestion!