What is the significance of photo DPI and how does it impact the quality of images?

The significance of photo DPI, or dots per inch, is that it determines the resolution and quality of an image. A higher DPI means more dots are packed into each inch, resulting in a sharper and more detailed image. Lower DPI can lead to pixelation and a loss of clarity in the image. Adjusting DPI can impact the overall sharpness and quality of printed or digital images.