You will need to "Tile" the pictureprint.
When Save As and a pic format, then click on the setup and you will find the Tile, Heigth x Width and divide that on 1 000 000 then you will get the numbers of Tile's to use, round it up
I think to remember i have seen that some have used max ( 256 ) as a standard, but not sure about that
V18, V19, V20, V21, 2015/ 16/ 17/ 18 Pro. Platinum
Deluxe V20, V21, 2015/ 16/ 17
Windows 10 Home Premium 64 bit, 32 GB
NVIDIA Geforce GTX 780m, 1 GB