There are no hard and fast rules about organizing a comparison/contrast paper, of course. Just be sure that your reader can easily tell what’s going on! Be aware, too, of the placement of your different points. If you are writing a comparison/contrast in service of an argument, keep in mind that the last point you make is the one you are leaving your reader with. For example, if I am trying to argue that Amante is better than Pepper’s, I should end with a contrast that leaves Amante sounding good, rather than with a point of comparison that I have to admit makes Pepper’s look better. If you’ve decided that the differences between the items you’re comparing/contrasting are most important, you’ll want to end with the differences—and vice versa, if the similarities seem most important to you.
Despite the name of the activity, traditional Picture Difference information gap tasks don’t produce a lot of this kind of language. However, you can easily adapt the task by giving students a range of pictures to compare and asking them to decide generally how similar or different each pair of pictures are (“A1 and B1 are almost the same” etc), and then some examples of differences and similarities “The most striking difference is…” etc) without looking at each other’s worksheets. It’s probably best if they write these sentences down. They can then look at all the pictures and change any statements which they now think are wrong.