If your store uses the Vintage theme, we recommend uploading square images, around 1200px square. The theme supports any size image, but it's best that you keep your images all the same dimensions so that your store looks tidier.
You can make this a lot easier for yourself if you change your store's built-in product image sizes. To do this, follow the instructions below;
To change the default image sizes that your Spiffy Store uses, you will need to do a couple of things… turn on advanced configuration options in your preferences, and then edit the product image sizes in your theme editor. Instructions on each step are below.
To add white padding around images, use the "Padded" option.
Or to crop parts of the image, use the "Cropped" option.
Resizing your images before you upload them gives you far greater control. Not everyone knows how to use image editing programs, which is why we have recommended the “Custom image sizes” option for most people.
Most people have some sort of image editing program that allows them to re-size or crop an image. There are plenty of free ones out there as well. There's a great one online at http://pixlr.com/ (Advanced Pixlr editor)
If you’ve got a handle on editing your own images… give it a go!
If you upload product images that are 1200px wide x 1200px high, then your photos should come out gorgeous on all pages.