Hi Samwise,
I actually had an e-mail from Jonathan at the weekend with a substantial list of suggestions (including some example code) and bugs that he's found in the current release of my BBC Micro Image Converter. I've added all of his relevant suggestions/bugs to the bug tracker.
Most of the bugs he mentioned I already knew about and have either already been fixed or are on my list to be fixed. There was one bug in particular though I didn't know about which only seems to affect monochrome BMP files causing them to be displayed in the wrong colour (e.g. instead of being black and white it ends up black and green).

I've managed to do a workaround for it just now until I can get a better solution.
Kind regards,
Francis