I will try to ask the people at Papier.com next week as to whether they know the exact dimensions of the square images that are needed.

At the moment I have used two of their square greetings card templates: one is full field where some of the uploaded image goes into the bleed areas, so the result fills the front of the card yet a little is lost at the edges: the other has a full picture with a white border around the picture. They advertise them as photo cards, and write about uploading a photograph, yet what is uploaded is a jpg file, so it does not need to necessarily be a photograph.

William

Upscaling can be very crude, which is why I would suggest doing it yourself and sending an image of the required dimensions to the printer.

The images start as 1024 pixels by 1024 pixels and are probably at 300 dots per inch.

So if a square template at Papier,com has a picture frame that that some larger value that is, however, not some exact multiple of 1024 pixels by 1024 pixels such as 2048 pixels by 2048 pixels, I am wondering how the larger picture is produced.

I am not here asking for the method used by Papier.com, I am just wondering if anyone here knows anything in general terms about how a bitmap of one size such as 1024 pixels square is enlarged to fit in a picture size that is, say, 1500 pixels square.

I know that if I were to know the exact size of the Papier picture frame that I could use Affinity Designer to place the original image on a white background of the picture frame size and use that image so that the original image would print at the exact original size.

William