Hi,
Using PHP, is it possible to embed a message inside an image, without it being visible to the viewer? - a bit like a digital signature?
You could probably add comments to JPEG files via metadata (e.g. IPTC, Exif, XMP), though I've never done it personally.
If you know the code for a comment using IPTC, you can use [man]iptcembed/man to add this information.
