Digital camera files of 2-3 megapixels should be adequate for most card sizes. View the chart below for minimum recommended pixel counts.
You will have the option to resize your image in the design center, so don't worry if your pixel counts are not exactly those shown in the chart. But do keep in mind that low resolution images will most likely print poorly - especially if you enlarge them.
For best results when scanning or editing photos in your preferred image editing application, prepare your image at the final size it will be on the card. Recommended image sizes to fill the card front for each greeting card size are:
Maximum Image Size for Small Card: 4.375"x5.625"
Maximum Image Size for Medium Card: 5.3"x6.825"
Maximum Image Size for Huge Card: 8.625"x11.125"
File Format Required: .jpg
Required Color Mode: RGB
Resolution: 150-250 dpi at final size (min. 150 dpi required)