Thing is, I've always referred to my favorite repeater as "chirp-img0001-", and that's how I label it in my radios. I hope your new feature can support my unique use case.
Yeah, I didn't give a lot of thought to the magic, perhaps I should throw something non-printable in there and be a little more strict about where it is in the file.
Changing the file extension seems like a pretty low cost way to support both formats and allow mere mortals to identify them in a directory. I can't think of a use case though... Pros? Cons?
The only pro would be sharing the file with older versions of chirp, either because they have something on an old machine and can't upgrade or are sharing with someone that won't. However, we've never dropped support for a major platform so I don't think there is any reason for someone to not upgrade.
I remember some consternation over the formats last time I tried to introduce one, which is why I'm loathe to make a big deal out of it. I think my preference would be to just note that it's happening and if there is real evidence of it being a problem for people then work backwards to support the old way.
--Dan