Short. If the image is intended to be viewed from a close distance, then 300 DPI is considered the industry standard. For large images, smaller values are usually used.

DPI is the number of dots per inch. The 300 DPI requirement means you can print a 3000×3000 pixel resolution file at 10×10 inches.

Large images are usually meant to be viewed from a distance. In most cases, if your file is 12000 pixels or more on its longest side, it can be printed at any size, as it produces 300 DPI quality at 40 inches or 1 meter longest side. This already involves viewing the image from some distance, and increasing the print size even further will likely involve proportionally increasing the viewing distance.

I wish everyone good luck in printing images and have a nice day.

Roman Meleshin.