Check what the platform actually asks for
Every store platform and marketplace publishes its own minimum image size and often a larger size that switches on zoom. These rules change, so read the current guidance for your platform before you decide how big the file has to be, rather than trusting a number from an old article.
Work backwards from that number. Look up the pixel width of your source and decide whether 2x or 4x gets you there. A product page also benefits from images that are a little larger than the minimum, because stores resize them down more cleanly than they scale them up.
- Read your platform’s current image size guidance
- Compare it with the pixel width of the source
- Pick the smallest scale that clears the threshold

