Attribution metadata

Attribution metadata

So I started using tiled to put together a water garden using some of the tiles already on http://lpc.opengameart.org/static/lpc-style-guide/assets.html, and had great fun doing it.  But I immediately realized a problem -- how am I going to keep track of which tiles I used where so I can provide proper attribution in the finished project?

Is there, and should there not be, attribution and license data in the .png files contining the tiles:  Should our tile editors be equiped to provide it?  Is this even compatible with the .png file format?  Do we need a new one? And should programs like tiled keep track of these data to embed it in as metadata in the finished landscape?

I've always felt that object code and executables should also have room for metadata of this kind, maintained by linkers and compilers and library tools. It could make it easier to tell if one has really produced free software, or whether something proprietary has sneaked in.  Or for that matter, whether your proprietary game accidentally has GPL3 content by mistake.

-- hendrik