What image file formats do you support? Which is best?

Zazzle supports images in JPEG, PNG, PDF, SVG and Adobe Illustrator (AI) formats. These formats will produce great quality products as long as the resolution meets or exceeds our recommendations. We support full transparency for PNG, PDF and AI files. This can be especially useful if you are creating a design with multiple overlapping images such as borders to go around your design, or shapes with non-rectangular edges. For PDF and AI formats, we support vector output for most of our products.  Please note that within the Zazzle Design Tool, a rasterized (bitmap) version of your vector-file will appear. If you have a vector file we recommend using that as it will produce better printed product results.