QRix
Cut the subject out and drop a plain white background behind it — the format listings, catalogues and documents ask for.
Result will appear here
Plain white is what most submission rules mean by "a plain background": nothing behind the subject to distract from it and nothing that varies from one photo to the next. It is also the hardest background to fake with lighting alone, because a white wall photographs grey unless it is lit separately from the subject. Cutting the subject out and placing white behind it sidesteps that entirely. The white is exactly #FFFFFF everywhere, which is what an automated checker looks for and what a lighting setup rarely achieves. One thing to look at before you submit: the edge. Where the original background was dark, a thin dark line can survive the cut and will be visible against white. Zoom in on the outline; if there is a fringe, a photo taken against a lighter background will cut more cleanly.
Yes — #FFFFFF across the whole background, which is what automated listing checks look for and what a photographed white wall almost never is.
Pixels from the old background that sat on the edge. They were part of the image before the cut and become visible against white. A lighter original background avoids it.
Yes, there are ten background colours, and transparent. White is only the default because so many rules ask for it.
Yes. If you need a JPG for a size limit, convert it afterwards — there is no transparency left to lose once the background is solid.
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