-Optimal Image Size: 750kb - 10MB
-Image Type: JPG or PNG
-DPI (dots per inch) : 300
-Dimensions: idealy 1800 x 1050 pixel OR more

TIP: Please take into consideration to add an extra quarter-inch (1/4") / 0.6 cm because the image bleeds in the printing process (this is more crucial when having a frame and/or cards zones/slots that are close to the frame's edges)