Conditional IMAGETYPE possible w/ CGI?

[Steve Lime]

Dave: I handle this on the client-side by changing the imagetype (in 5.0 this
would be done using &map.imagetype=JPEG or map.imagetype=PNG) as
necessary just before submitting the request. Here's a site that does just
that:

  http://www.dnr.state.mn.us/maps/fom/mapper.html

Only when the orthophotos are on do I request jpegs. Otherwise it's a gif.

Steve

>>> Dave Fuhry <dfuhry at GMAIL.COM> 09/17/07 1:11 PM >>>
I'm using CGI mapserver, and would like it to return JPEGs when an
ortho layer is active, and 8-bit PNGs otherwise.

The CGI reference makes no reference of an exposed IMAGETYPE or
equivalent parameter.  Variable substitution in the mapfile (IMAGETYPE
"%param%") doesn't seem to work.

Are there any easy ways to conditionally specify the IMAGETYPE using
CGI mapserver, or will I have to preprocess the mapfile?

Thanks,

Dave Fuhry