If you are uploading photography or non-vector artwork (e.g. high-quality JPEGs), please make sure they are no less than 575 x 412 pixels at 96dpi or ideally sized at 1794 x 1264 pixels at 300dpi. If your designs are a mix of photography and design, make sure the embedded photographs used are above the recommended pixel sizes.
* may appear blank until opened in Adobe software. Please do not save your design in the 'artwork guidelines' group layer or it will not print.