Dimensions
A solid rule of thumb is that the best prints come from large, high-resolution files. This time, when we say "large," we mean "resolution," not file size.
It's important to know the difference between file size and resolution, which are both measured in pixels. When it comes to printing, it's all about the pixels.
Requirements for Product Size
There is a file size requirement for each product provided on the Grand Canvas marketplace; that is, the lowest resolution a file must meet in order to be eligible for printing with that product.
We recommend beginning with 7632x6480 pixels if you want to utilize a single picture file for all of your products. We are unable to accept images larger than 300Mb, or 15000x15000 pixels, because of the strain they put on our systems.
Also, keep in mind that the final image you submit is unaffected by the DPI or PPI you choose.