Multiple images appearing sequentially

Sure it's possible, but what exactly do you want to achieve? images appearing in different parts of the slide or one over another, or in some other way perhaps?

Well, I'll try to put it in simple words. Let's do it with two photos first, and you can do the same with more after you get the idea.

1. Add two photos with Add Layer, let's call them Pic01 and Pic02.

Now look right - you see Pic01 and Pic02 under Layers. They are on the layers list now, and you can select the one you need to work with.

2. Now drag Pic01 over Pic02 (so it covers Pic02 completely).

3. Select Pic01 on the layers list and switch to Animation.

4. Add keyframe 2 for Pic01 and change the Opacity setting to zero in Keyframe 2.

That is, you make Pic01 gradually disappear, and Pic02 will become visible.

Hope this helps!