When working with the 2D virtual shelf application, the artwork/SKU images need to be the following:
Images of products must not be lower than 650 pixel on any side, this is not the DPI
simply the length of pixels an image has to have on at least One side.Images must be a PNG
Unless agreed otherwise (subject to fees), the background of the PNG must be removed so that the product image does not appear as a square on the shelf
The naming of the product images must be a SKU.png, for instance:
2000344.png
If there is other views for each product, i.e. back, or side etc. Then it must be like so:
2000344_back.png
2000344_left.png
(also, for more information on correct SKU naming, please see Using a Macro to Find missing images and Image Barcodes Matching).