Image resizer.

Upload a landscape photo to an Instagram feed post and the platform crops it to a square, usually through the middle of whatever mattered. Upload the wrong ratio to Facebook and your headline gets clipped. Set an Open Graph image at the wrong size and your link previews arrive letterboxed or, worse, blank.

The presets here cover the sizes that actually come up in small business work: Instagram square, portrait and story, the 1200×630 that Facebook, LinkedIn and Open Graph all effectively share, YouTube thumbnails, and a standard blog header. Pick one, drop the image, download something that fits.

There is also a plain maximum-width field, which is the one you will use most for websites. Set it to the widest your layout ever displays — for most content columns that is 800 to 1200 pixels — and everything larger scales down proportionally while smaller images are left alone.

Worth knowing

• 1200×630 is the size to get right first. It covers Open Graph, Facebook and LinkedIn previews in one file.
• Never scale a small image up. Enlarging adds pixels without adding detail and looks soft everywhere.
• Keep text well inside the frame. Platforms crop the edges of previews differently on mobile.