Image resolution is is calculated in pixel width and pixel height. An image of a 12 Megapixel camera has approximately 4000 pixel (px) image width x 3000 px height: 4,000 x 3,000 = 12,000,000 or 12 MegaPixel.
As a rule of thumb, an image with a resolution of 4000 px wide and 3000 px high can be used to print a wallpaper mural that is 4000 mm wide and 3000 mm high. The camera, size of the camera sensor, the lens are also an important part in the final quality of the large-format print like a wallpaper mural.
Guarantee: We check every file you upload or you choose from the image library if the resolution is suitable for your wall size and print size. If we are in doubt, we will contact you before printing and discuss it with you.
Please see below two screenshots of information about the pixel size of an image on your computer via PhotoShop or the Finfer on your Mac.