We recommend using square images, around 600px. The reason is that when Spiffy Stores resizes an image, it maintains the aspect ratio.

For example, if you upload a product photo that is 400 × 600 (a tall rectangle), then display it using the “medium” size (as Minimal does on the home page and collection pages), then it will display as 180 × 240. Similarly, if you uploaded a 600 × 400 image it would be resized as 240 × 180. Both of these examples will display “fuzzy” in the minimal theme, as it stretches images to fit so that they are always square.

Uploading an image that is 600px square means that all of your images will appear crisp and clean. They won’t appear to be stretched on any of your pages, and they will be sharp in the lightbox (when you click on the image in the product page).