[tuxidomasx]

This reminded me of a steganography blog post I wrote back when I was doing computer security.

It should be possible to binarily concatenate compressed (RAR'd or ZIP'd) text data directly to a JPG.

Then you can save it as an image on the client, or uncompress it in the client browser and read the data.

The differences are 1) the saved image won't look like random pixels-- it'll look like whatever base image you choose and 2) you don't have to worry about writing the encoding/decoding data as bitmap stuff.