Hi taffyapple

You will need a graphics program of some kind - for this kind of simple conversion I just use 'Preview' which is a component of Mac OSX.
You could ask a question about this on the PHotograph Restoration board, as it depends on what operating system your computer uses, but there's a wide range of software available and the Photo Restorers have tried pretty much all of it! So they should be able to advise you.
Cheers
Prue