I have a jpg of some logo, but its background is not completely white, more like light-greyish, whereas I would like it to be perfectly white.
I know how to select the background and also know how to turn that background to transparent, but not how turn that background to white.
If it can't be done with Preview, I also have iPhoto. I don't know how to do it there either.
NB: If the thing needs to be converted to a png in the process, that's fine.