Adding images can be creatively daunting, KB effect aside, I look at some of my earlier works or 'life celebrations' and see too may zig zags to find "the person" in their class or family picture, zoom in on one, zoom out on another, pan left, pan right - I know! I can get monotonous! I really don't go for wipes and other effects but I will say, if I had to do some of my early stuff again, I would stick to fades as my primary tranisitons between images and save the KB effect for some really special and rare images - reducing the amount of sea sickness! My advice, don't feel compelled to 'work' every image - but do leave it on the screen long enough for what the audience will appreciate seeing. That being said, I can think of two ways to introduce images that many people don't use. Picture in picture (still+still) and movie + picture. In one of my videos I had an image of the company founder, but no video of him. I put the image of him on the right of the screen, composed a podium in front of him, on on the left of him I put a large projector screen and had images of the different company braches appear on the projector screen. I also transitioned the podium to indicate a company name change.
Combining video and images, I had images disolve and on off screen while folks reminised about the 'ol days'