Most marketplaces it is ideal to use 1:1 photos and crop to have the item fill as much of the space as possible. Vinted previews are more like 5:7 which leads to photos which were optimally cropped for other platforms being cut off in the previews. It would probably be ideal to automatically pad images with extra whitespace if the background is already white and the item is detected as taking up most of the width of the image.