Item images are distorted

[kimsheu]

Hi, I'm using the Atlas theme for my Square store and I noticed that the item images look fine on the main page but are stretched out when my colleague opens the individual item "pop-up" pages to check out.

They are all square jpgs at the recommended 720 x 720 pixels, anything I can do here? 

[Sean]

It sounds like the images may not be a high enough resolution. How did you resize the images? How large are one of your image files? 

[lainworks]

Where do you find the specifications for image resolution and size?

[trylovdesigns]

I would like to know this, also.  Where do we find specifications for image resolution and size!