What is resolution and DPI?
Monitor resolution is the amount of pixels on a screen (monitor) measured horizontally and vertically (such as 1900×1200). DPI is the dots-per-inch that would be printed (such as 300 DPI). Print resolution is measured in DPI. As an example, a 900×900 pixel image printed at 300 DPI would be 3×3 inches. The same pixel image at 600 DPI would be 1.5×1.5″. Ideally 300 DPI minimum photos are needed for print, and 72 DPI for web.