I think that is the root of your problem.. text columns are for.... text!
Its better to use a blank page or a customised page for your images.
You could try this, Select Shapes top menu - choose one - it will appear on your page, size it to suit.
Now you can drop your photo, as you do hover over the shape and a blue inner line should show, if so drop the image and it will sit inside the "shape", if not delete and repeat.
Putting images over flowing text columns can create problems, if you have flowing text or add later in a page previous to the images... the text will skip around the images and appear at the next usable column on a page.
You can also try the Insert menu option, but I found without a place holder, wierd things can happen.
What proportion of your book do images make?
Ideally if its a lot, its wise to create new pages in the template, slide the Book bar down to reveal the layout panel, select a blank page, copy and paste it, select it and add shapes. Set their position as suits you and save changes. Close the layout panel, and add a page.. selecting your new photo page.
Any problems, just get back to here and I or somebody else will take it up.