When Fotomoto adds images from your website to your Dashboard, the system considers each image file to be unique based on it's URL. Your website may show the same image with different URLs, for example you might have small and full-size files for the same image at different URLs like this:
Fotomoto treats the files separately by design, giving you the control over which image(s) the Buy Buttons will appear on. To help you tell the difference between the two files (shown in a below), you can view information about the duplicates by hovering over the image and clicking the information icon to view the image dimensions (shown in b below).
Managing multiple versions
If you don't want certain images to be for sale, you have a few options on how to exclude them from your store, as explained in How do I exclude a photo from my store?
. It's easiest to move the versions you don't want to sell to the Not for Sale Collection, but if you have a lot of images it might be preferable to add the "nofotomoto" class to the image tag in your page template.