Given how Fotomoto works, Fotomoto can't tell how big your high resolution files are based on the low resolution image on your website. So to avoid a customer purchasing a print size that's bigger than the resolution your image can handle, your options are to:
a) Pass in the dimensions of your high resolution file and Fotomoto will automatically disable any larger print sizes.
b) Disable any print sizes that are larger than the resolution of your images can support - this is explained below.
Recommended resolution
Fotomoto recommends that your "original" high resolution (print) images be between 200dpi and 300dpi. See preparing print-ready files for order uploads for more information. If you sell a print and upload an image that doesn't have enough resolution, the order status will change to "Waiting for approval" and you will see "WARNING: Resolution too low: image is [current width]x[current height]; we need at least [recommended width]x[recommended height]]" next to the image after you upload the file. You can choose to "Print anyway", but we don't recommend it, and we won't be responsible for any customer complaints about print quality.
How to calculate the maximum print size to offer
- Find the resolution of your original image file. Say for example it's 3872px x 2592px.
- Divide each dimension by 200 (the minimum recommended dpi). In this example it would be 3872/200 x 2592/200 = 19.36" x 12.96".
- The resulting size is the largest print size we recommend you print for that image - in this example we'd recommend you disable any print size larger than 19.36" x 12.96".
Questions? Please feel free to contact Fotomoto Support - we're glad to help!