Start with a master, not a marketplace copy
Your best photo should be the file you preserve. Keep the highest-quality original from your phone or camera and avoid using an already-compressed marketplace download as the source for another marketplace. Every time a JPEG is resized and recompressed, you can lose some detail.
A simple product folder works well: keep an Originals folder untouched, then create separate export folders for each destination. That gives you the freedom to regenerate a listing later without hunting for the original image.
Aspect ratio matters as much as dimensions
A 1600-pixel image can still look bad if the product is cropped at the edge. The shape of the destination canvas matters. Square canvases are common in ecommerce interfaces because they work predictably in grids. Wider canvases can be useful in other contexts. The important part is deciding whether to fit the full product inside the destination or crop the image to fill the frame.
For most product listings, preserving the whole item is safer than aggressive cropping. If the source image is extremely tall or wide, a little clean padding is usually preferable to cutting off a handle, label, shoe toe, collectible box, or other detail a buyer needs to see.
Don't confuse maximum quality with maximum file size
Modern phone photos can be several megabytes each. Uploading the full originals to every marketplace rarely gives buyers a noticeably better experience, but it can make uploads slower and create unnecessary storage and bandwidth use. A good export workflow reduces file size while preserving enough resolution and JPEG quality for a clean listing.
The source should stay untouched. Compression belongs on the destination copy.
Use platform presets as workflow helpers
Marketplace rules and recommendations change. Presets should make repetitive preparation easier, not become a substitute for checking a marketplace's current documentation when a listing is especially important. A useful preset handles canvas size, fit/crop behavior, JPEG quality, and filenames consistently so you do not repeat those decisions manually for every photo.
Build a repeatable sequence
Put the hero image first, followed by alternate angles, labels, accessories, close-ups, and disclosed defects. If you rename files, use a predictable base name plus a sequence number. This keeps the same photo order across every marketplace and makes it much easier to troubleshoot a listing later.
SellerPic's approach
SellerPic Free takes a batch of source images, lets you choose marketplaces, applies destination presets, optionally renames the files, compresses the output, and produces one ZIP with separate marketplace folders. The originals remain on your device during normal processing.
Marketplace names and trademarks belong to their respective owners. Presets are workflow aids and are not a guarantee of third-party platform acceptance.