I do this very frequently on Mac. Here’s how I do it. I paste all the images into Microsoft Word. You can paste anything into Microsoft Word. Then I take a screenshot and then I annotate it with Skitch.
I also recall Word being not very easy with alignments.
So use Pages. It came with your Mac.
I also would like to do some small changes to the images(maybe laser eyes? maybe draw some lines to emphasise an emotion?).
Preview. It also came with your Mac.
If you look at my original post, I say that Preview is very powerful but hard to use.