S Fielding wrote: Sorry about replying to myself but I've played with this some more and it does seem to do what it says on the box. I created a gimp gap animation of a few slides (pic_00001.xcf, pic_00002.xcf etc) and opened the first one manually. Then I mapped "note 00 on" (on channel 15) to plugin-gap-next and "note 02 on" to plugin-gap-first. Finally, I connected a vkeybd to gimp in qjackctl. Playing low C's stepped through the slides perfectly and low D restarted the show. The only caveat is that, if you wish to use a spare MIDI channel rather than respond to every channel, you will need to apply the patch I mentioned above to your install of gimp. Hope this is helpful to somebody. Simon