Let’s make this clear with a few examples. You have probably heard many times that 300 DPI is needed for high-quality prints. Of course, this has its justification. At this value printed graphics can be viewed at a distance of 25 to 30 cm without individual pixels standing out and being perceived as disturbing, but – and this is decisive – the value says nothing at all about the size and quality of an image, because:
any digital image, no matter how tiny, can theoretically be output in 300 DPI.
Assuming you have an image with pixel dimensions of 300 x 300, the image will be what size when output in 300 DPI? – Correct, 2.54 cm x 2.54 cm (see example 1 below) – that is about the size of a postage stamp. Now let us take a square image with 3000 pixel sides. So if output in 300 DPI, the image would be 25.4 cm high and long (example 3). Conversely, an image with pixel dimensions of 300 x 300 can also be output so that it has a side length of 25.4 cm. The corresponding DPI value would then be 30 (example 2). And, of course, you can output an image with 3000-pixel pages in postage-stamp size (DPI value: 3000). Of course, you would have to take a magnifying glass in hand to capture all the details.