Image color to alpha

Stage 1 – replace options (to alpha)

Replace color to Replace everything except this color All lighter colors (replaces everything from white to light gray) Threshold: darkness ≤ % Also replace semi alpha

When active, existing semi-transparent pixels are made fully transparent as well.

Stage 2 – color the rest

Color everything else Color:

When active, all non-transparent pixels are colored in this color.

Drag your JPG/PNG here
or click "Choose files…"

Order: apply transparency first (incl. the semi alpha option), then optionally color the rest.

"Also replace semi alpha": existing semi-transparent pixels are made fully transparent in stage 1. Fully transparent ones stay transparent.