There is something else got broken with this change. If pan and zoom is enabled, the animation isn't applied when pressing "next." This is changed from how it worked previously, in version 22.0.55 and before. The setting "Disable transitions on manual image change" has no effect at all, from what I can tell.
I don't know what could have possibly motivated you to make this change in behavior. But won't you do what you can to mitigate the impact on your customers who liked it the way it was? The best - the most customer friendly - thing you could do would be to make an option for whether slideshow is paused on "next". The next best thing would be to fix it so "Play" resumes. Even better, make it so if "Play" is pressed while the slideshow is running it advances to the next image, without pausing. This would actually be a decent solution. It would restore the functionality lost by pausing on "Next", while pausing on "Previous" isn't actually that bad, not for me. If I'm returning to the previous image there's a good chance I want to pause on it.
And fix the behavior associated with the "Disable transitions on manual image change" option, please.
I think what I'm asking for is not unreasonable. If resources is an issue, will you at least indicate whether you will put this on the to-do list?