dotPhoto Club Accounts
As of July, 2016, the longest side of an image that dotPhoto will store is 6000 dots, so the largest megapixel image (MP) image dotPhoto stores is 6000 x 6000 or 36 megapixels.
The largest file size is 20 megabytes. If you have a 36 megapixel image, you may need to drop your JPG compression ratio slightly (perhaps 5%) to stay under the 20 megabyte upload limit. That is a very large file, and you will not see any difference when printing any product that dotPhoto offers.