Marketplace photos have one job: help someone understand the item quickly enough to trust the listing. That means the image should be clean, readable, and sized for the platform without looking over-processed or cluttered.
A marketplace image is easier to rescue when the item is already visible. Even light, a simple background, and enough space around the subject will usually beat a dramatic photo that looks nice but hides the thing you are actually trying to sell.
Do the cleanup first. If the background is messy or irrelevant, remove it before you worry about exact dimensions. That gives you a cleaner export and keeps the sizing step focused on delivery instead of damage control.
Distracting backgrounds, stray objects, and shadows that make the listing feel less consistent.
Shadows or context that help the customer understand scale, texture, or product shape.
Thin edges, reflective materials, straps, hair, and transparent parts are the usual trouble spots. Zoom in before export and make sure the cutout still looks believable when you view it at the size the platform will show.
Different marketplaces display images differently, but the principle stays the same: the image must be large enough to stay crisp while still matching the platform's layout. Resize after the cleanup so the final file is already in the right shape.
If the source file is small, upscale only enough to reach a usable result. Bigger is not automatically better if the export starts to look synthetic.
Keep a clean master export so you do not have to repeat the whole workflow for every channel. A good product workflow usually produces one main cleaned file, then several platform-specific variants from that file.