- Can be square or tall rectangle.
- Placement of product(s) must be consistent; i.e., all product dead center with a good amount of space (15% of total width/height for each edge) around the top, sides, and bottom of the frame (NO tight crop).
- Orientation must be consistent; whether you opt for square or rectangle, the choice must be used for all of the product photographs.
- Color/lighting/tone must be consistent throughout product photographs.
- The maximum product image size allowed by Shopify 2048 x 2048 pixels. For the best magnification, use this maximum dimension for width and/or height.
Hero, header, and other photographs that will be used in the design of the website
- Horizontally oriented photographs with a good bit of negative space for hero images (at least 60% of image should be available if we are to apply text to the image).
- In general, horizontally oriented photographs work best because browsers still account for the majority of webpage views.
- Photographs should be at least 1,800 pixels wide and high resolution.
- Vertically oriented images will likely not be used unless they can be incorporated into a diptych.
Page photographs (head shots, space shots, and other images included on pages)
- A lot more freedom here; as long as they're high res and look good (subject matter is clear) at a minimum of 450 pixels, usually anything will work.
Edit June 8, 2016: Looking for some good stock photography options? Look here and here!