A list of URLs for previewing a low-resolution version of the artwork. For JPG and PNG file formats, there's a separate URL for each page. For PDF file formats, there's one URL for the entire preview. The URL is in the form https://partnership-artwork.canva.com/<export_file>. If you're using the China version of the SDK, the TLD is .cn instead of .com. You can take the necessary security measures to protect the URL from any malicious attacks.