Strange though, as others on the forum have mentioned something strange recently with images too. There might be something odd going on that (as yet) I haven't been able to reproduce.
It'd be interesting if when adding images and anyone has a problem that they mention it and we can see if there really is something going wrong more regularly!
The dot on the end of the image URL shouldn't be a problem - Voice will ignore it. (for assets, any file extensions are silently ignored - so you could put .jpg on the end of the image URL if you wanted to. I can't remember exactly why we did this but I think it was to work around a bug in Firefox about a decade ago!!)
Thanks
Joe