Resolution measures how much detail an image holds, usually counted in pixels. A 1920 by 1080 display has just over two million pixels. A 4000 by 3000 photograph has twelve million. More pixels mean finer detail and larger file sizes. The term also appears in print, where resolution is measured in dots per inch. A newspaper might print at 150 dpi. A glossy magazine needs 300 dpi for sharp photographs.

Confusion arises because screen and print use different units. A web image at 72 pixels per inch looks fine on a monitor. Send the same file to a printer and it will look soft. The rule of thumb for print is 300 dpi at final size. For screens, what matters is the pixel dimensions, not the dpi number, which is often just metadata. Designers working across both media keep high-resolution originals and export smaller versions for the web.

Practical guidelines

• Print: 300 dpi at final output size.
• Web: match pixel dimensions to display size.
• Retina screens: export at 2x for sharpness.
• Keep original high-res files archived.

Resolution is not quality by itself. A high-resolution image can still be blurry, poorly lit, or badly composed. But without enough pixels, no amount of editing will save it.