adding code to a picture

[JohnnyBravo]

Any advice on what program to use to embed code into a picture to maintain rights?

JohnnyB

[Black Spot]

Irfanview

[arenhaus]

Or XNView. Anything that edits IPTC codes.

Even Photoshop, but it uses its own incompatible metadata system, so unless all parties involved use Adobe products in their work, it's better to stick to IPTC.

Or, if you want a digital watermark embedded in the image raster itself, Digimarc is the pioneer in that area. But after they had changed their pricing policy a few years ago, they want quite a bunch of green for their codes.