What is 300 Dpi?

DPI or Dot-per-inch can refer to printer resolution. If an image has 300 dpi, it means there 300 dot-per-inch throughout the image. The problem with increasing the dpi is the size of the image increases as well. When uploading images to a website, the image may take too long to download when a user views the site, especially if the user has a dial-up connection.