What does resizing an image do?

Resizing changes how many pixels an image has. Making it smaller cuts the file size, which helps with upload forms, email attachments, and web pages, where a photo straight from a phone has far more pixels than any screen shows. Making it bigger adds pixels but no new detail, so enlarged images look softer. Keep the aspect ratio to avoid stretching, or set both sides to fit an exact size.

Tool description

Open an image and the width and height fields show its current size. Type a new width and the height follows to keep the proportions, or type the height and let the width follow. Turn off "Keep aspect ratio" to set both sides yourself. The preview and the size under it update as you type, and the download has exactly the size you entered, as PNG, JPG, or WebP.

Features

  • Width and height in pixels, with the aspect ratio kept or free
  • Clean, sharp results even for big reductions
  • Transparency kept in PNG and WebP
  • Runs in your browser, so your images are never uploaded

How it works

Shrinking an image in one big step skips most of its pixels, which makes thin lines and fine textures look jagged. The tool halves the image step by step until it's close to the new size, then draws the last step with the browser's high quality smoothing. Every step averages the pixels it merges, so small versions stay clean.

Tips

  • Empty a field and click elsewhere to get the original size back.
  • For web pages, saving as JPG or WebP keeps photos much smaller than PNG.
  • Enlarging a small image won't bring back detail. If you need a bigger version, start from the largest original you have.