Our plugin works with png images of the same size with transparent backgrounds. Recommended size for the PNG images is 1500px X 1500px. Squares work best in general.
Each png image represents a transparent layer with the product component on the product preview. The software stacks images automatically – showing different product parts on top of each other. You can create a full representation of the product and offer a true ‘Build Your Own Product’ experience.
Here is a folder with sample product images: https://drive.google.com/open?id=0BxXbvqoSPF5FMEFrdEdvejYxZk0
We have one store that also uses transparent layers to recolor the base product wireframe: gatcreek.com – one layer for base, 1 layer for grain, 1 layer for different colors.
Please note that if you upload big images (for example 3500x3500px) each more than 1 MB the custom product page will LOAD VERY SLOW. So please use smaller images (up to 1500px).