Photos you must not edit
Some photographs are evidence. A recolour tool can do a great deal to a picture, and for those photographs the right amount is nothing at all.
Identity photographs
Passport and visa photographs are checked against the person. The rules for them say so directly: a colour photograph, a plain white background, even lighting, and no alteration by software — no filters, no retouching, no changed colours. A recolour of the shirt, the background or the eyes in such a photo turns a valid photograph into one that may be refused, or worse, treated as altered.
So this site offers no “passport background to white” preset, and every page that opens on portraits carries one line: do not use a recolour on a photo you will submit as ID.