We do not keep image specifications but there are tools, or browser add-ons that allow you to see details about the images you uploaded on your site. However I feel that there is no need for you to re-upload all your images since Fotomoto will not use the low-resolution images for prints.
Once someone orders a product from your store (a print or for download) Fotomoto will need a high-resolution file from you and there are two ways for you to provide them with that:
You can either wait for an order to arrive and Fotomoto will email you asking for the high-resolution files needed
or you can activate the Auto Pickup feature that they offer, where the file needed can be automatically taken from your online storage.
You can read more about these options here.
Compatibility of image requirements between Livebooks and Fotomoto