Photo formats
Upload a JPG, PNG, or HEIC. HEIC is the default format on iPhones, and the builder takes it directly, converting behind the scenes where a browser cannot read it. There is nothing to export or change first.
Finished designs
If you are uploading a complete card design instead of a photo, the upload accepts JPG, PNG, HEIC, or WebP at a 5:7 ratio, ideally 1500 x 2100 pixels and at least 750 x 1050.
What matters more than the format
Any of these formats prints well if the file is the original. What hurts print quality is how a photo was handled before upload: screenshots shrink it, messaging apps compress it, and social media downloads strip it down. Go back to the camera roll or the photographer's full-resolution download.
A photo that looks sharp when you zoom in on your screen will print sharp on a 2.5" x 3.5" card.