Read Essential Image Size Guidelines Before Registering For A Vendor Store:
Your vendor store logo should be a 520 x 520 pixel square .jpg. The main store banner should be 1200 x 520 pixels in .jpeg or .webp format.
For mobile, use a 520 x 250 pixel landscape image and a 360 x 210 pixel rectangular logo. Product images should be 600 x 600 pixel square .jpgs.
The maximum file size is 150MB. Use online tools to resize images, preferring .jpg for products and .png for logos. Upload multiple 600 x 600 pixel images per product for different views.