ImgReview has number of cool features, let me show you some of them.
You can add as many images as you want. So it's never been that easy to compare several images side by side.
The main feature that caused me to develop this app. You can add different shapes and (of course) arrows to make your point.
You can copy your whole work to the clipboard in one click and then paste it in any app of your choosing: gmail, slack, docs, you name it.
Add "human" touch to your work. Sketchify will add a bit of imperfection to your shapes, making it unique.
You can easily add emojis. Also if you make them bigger, they will really stand out.