More pixels than Full HD, still 16:9
QHD vs 1080p vs 4K
1920×1080 is Full HD. 2560×1440 is QHD/1440p (same 16:9 ratio, more pixels). 3840×2160 is UHD/4K. This page is the middle: sharp on a 1440p monitor without a 4K-sized file. Do not send 2560×1440 to Instagram; the app will crush it. Do send it as a desktop wallpaper or a product screenshot on a docs site viewed on a QHD panel.
Screenshots and UI marketing
If you capture a 1440p app window and downscale to 1920×1080, thin type goes mushy. Keep 2560×1440 for “retina-ish” web heroes that might display at 2x on a 1280 CSS-pixel layout (1280×2 = 2560).
Source quality
Enlarging a 1280-wide photo to 2560×1440 will look like a stretch. This preset is for sources that already have the detail — camera RAW exports, 1440p screenshots, design exports at 2x.
Weight
A 2560×1440 PNG screenshot can be 5–10MB. Use PNG for UI with text; JPG for photos. Compress once for email. Do not run Maximum compress three times.