Choose a solid background that separates the subject clearly and inspect the exported PNG at its intended display size.
Think about contrast first
After reviewing the transparent cutout, choose Custom color and set the color field. Look for enough contrast between the subject's main shapes and the background. A blue shirt against a nearly matching blue surface may disappear even when the mask is accurate. Brightness differences can matter as much as color names.
Check difficult edges on the new color
A darker background can reveal pale fringes from the original scene. A very saturated background may show those fringes more strongly than a neutral one. Switching colors does not repair the edge; it only changes how clearly the defect appears. Use a better source or a manual editor if the result needs correction.
For a simple author card, try a restrained background that keeps the face recognizable when the image is small. For a playful thumbnail, stronger contrast may be appropriate. Compare at the actual display size instead of choosing from a large, flattering preview alone.
Understand the export
The downloaded PNG includes the chosen solid background. The color is no longer a separate editable layer in that file. Export a transparent master too if you expect future changes. ToolNivo does not add text or a complete layout here; combine the cutout with titles and other graphics in your design editor. Make a final check after those elements are added, because their colors can change the balance of the composition.