I've been building CleanWhiteBG (https://cleanwhitebg.com) — a browser tool that turns product photos into clean white-background images. Full disclosure: it's my product, so weigh this post accordingly.
The most useful thing I learned while building it: white and transparent are not the same decision. Marketplaces like Amazon and most store themes expect pure white (#FFFFFF) so the photo blends into the product grid; a transparent PNG is the right call when the page background isn't white or you're layering graphics on top. And if the shot has a baked-in background, no CSS trick saves it — the cutout has to happen at the image level.
The other lesson: edge quality is where the real work is. Hair, jewelry, and soft shadows are what separate a convincing cutout from an obvious one.
How do you all handle product imagery — shoot on white from the start, or fix it in post?