Cut out the subject once, then try scarlet, crimson or brick red behind it. Preview live and download a JPG.

Red draws the eye first, which is why sales banners, food brands and holiday campaigns use it. Cream, white and light wood products have the strongest contrast against it.
Scarlet (around #dc2626) is the classic bold red. Crimson (around #b91c1c) is deeper and reads as premium. Brick or terracotta red (around #b4533c) is warmer and suits ceramics, candles and food.
A red product on a red backdrop disappears, and red reflects onto glossy and white items. If the edges look pink, switch to a deeper red, or use a neutral background for the main listing image.
Pick any shade in the Change Background Color tool, or start from a color below. Marketplace main images usually need pure white, so use the white background tool for those.
Upload the photo, let the tool cut out the subject, then pick a red swatch or use the color picker for an exact shade. Download the result as a JPG.