I'm still testing my site and just trying to get the basic running before I muck around with custom themes.
I've been having several issues with default gallery behavior. Most recently I create a gallery with 5 specific images. When I view the page, only those correct 5 display. When I view the media library only those 5 images are correctly attached to the applicable page.
However when I click on one of the images (from within the page) and cycle through the gallery, it somehow adds a 6th image. WTF?
I've deleted and recreated the gallery. I've even deleted and re-uploaded the problem image. But the gallery still "magically" pulls that image into the gallery when it is NOT included in the list.
Here is the gallery as I'm testing it right now.
I've also run into other problems with the "gallery" function (from within a Post) where one gallery would seamlessly cycle into other images or the thumbnails wouldn't link to anything at all once clicked. But for now I'd like to figure out the immediate problem above :)