1st rule of ecommerce is have fantastic imagery for your shop.
2nd rule of ecommerce is make sure all your imagery has the same aspect ratio.
Ok, maybe I made those up but look at any fantastic looking online shop and you'll see these two rules applied.
Unfortunately there are many shops that don't have the time or means to crop all their images accordingly so I created an collection template that will create a lovely montage of mixed imagery.
Simply choose the assorted template from the setting in your collection(s).