Hi there - I didn't see a looping control available from the command line.
have I just missed this?
No, I guess I forgot that some people might find it useful. I'll add it in the next version 2.2 (soon)
Meanwhile (if you're on Windows) you can edit acTL chunk using TweakPNG 1.4.0
OK great; I may add it to the source and build it here on my OS X box.
I can see where you drop in the 0 when building up the acTL
oh and thanks for the mention of TweakPNG - hadn't heard of it.