thanks to everyone for their comments & suggestions. Its certainly helped me consider things I hadn't thought of before.

httptech - the bitmaps would eventually be stored on a webserver. the numeric options & subsequent input would ideally be done as part of the web page containing the bitmap.

for now, the bitmaps are stored in a directory on the development machine. when development etc has finished they (& the perl scripts etc) would be moved onto a web server box.