Claris had something out at one time, not sure what it was called or even if it was available for Mac (it may have been a Windows product).
Something that may do the trick for you is the Kid Pix slide show program. You can only play the slides for 30 seconds but you have transitions and can even record a sound over it. You can get it by hunting down Kid Pix Companion (which goes on top of Kid Pix), Kid Pix 2 (which is KP + Companion), or if you have a 640 x 480 monitor or larger, Kid Pix Studio (VERY easy to find on eBay).
Of course, there's also PowerPoint. I think the original version came out in the late 1980s sometime. I remember an old version of it being on the System 7 compatibility chart they used to hand out with the System 7 upgrade kits.