VO standard for JPEG with WCS

[Pierre Fernique]

Hi all,

Some projects are using JPEG images with WCS keywords or FITS header 
memorized into a JPEG comment segment (DSS colour images from MAST, SDSS 
JPEG images, Aladin JPEG images,...).

Unfortunately these methods are not compatible, not documented and seems 
to evolve.

Could we have a kind of VO standard related to this point ?

One suggestion would be to put the FITS header - or a portion of the 
FITS header - into a JPEG comment segment (starting with FF FE) directly 
in ASCII but with the possibility for wrapping each line by a CR instead 
of keeping the 80 character FITS justification. By this way, a simple 
"strings" command (or equivalent) allows to display immediately the 
metadata. Another advantage, and not the least, is to have the 
possibility for keeping all the FITS metadata.

Good idea ? Bad idea ? Other suggestions ?

Regards
Pierre Fernique