You can try to read the environment variable HTTP_ACCEPT.
In this Variable the browser should list all suported MIME Types.
HTTP_ACCEPT 'image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, image/png, */*'
Thanks. I am able to read the HTTP_ACCEPT header. However I notice that some monochrome phones also accept .gif format. Do you know how I can differentiate a monochrome phone browser from a colour one from the HTTP_ACCEPT header information?