In the POS app, a square image is displayed. If you upload a non-square but a rectangular picture, then the system suggests to crop it to a square shape.
During uploading of the image, the system allows you to select the position of the image relative to the displayed (square) shape if it does not fit into it (along with the length or height), and increase or decrease it relative to the displayed shape.
Images that do not exceed 500 X 500 px are loaded unchanged. Images that are larger than 500 X 500 px are reduced to this size.