Image Resizer

Resize, crop, rotate and convert images - entirely in your browser. Nothing is uploaded.

Drop your image here

or browse files  ·  paste Ctrl+V

PNGJPGWEBPGIFBMPSVGTIFF

How to use

  1. Drop an image onto the upload area, or click to choose a file.
  2. Enter your new width or height; the other dimension follows if Lock Aspect is on.
  3. Pick output format (JPG, PNG, or WebP) and quality.
  4. Press Resize to render the new image in the preview.
  5. Download the resized file or copy it directly to your clipboard.

Frequently asked questions

Does resizing reduce file size?

Yes, usually significantly. Halving the dimensions cuts the pixel count to a quarter, which dramatically reduces JPG and PNG file sizes. WebP often shrinks further than the equivalent JPG at the same visible quality.

Is the resampling high quality?

The browser canvas uses bicubic or bilinear interpolation depending on the platform. Results are sharp for downscales; large upscales naturally show softness or blockiness regardless of tool.

Are my images uploaded?

No. Resizing runs entirely with Canvas in your browser, so the file is never uploaded.

Can I batch resize multiple images at once?

Currently the tool resizes one image at a time. Batch mode is on the roadmap for a future release.

Dimensions, aspect ratio, and the one rule about upscaling

Resizing changes the pixel grid. Downscaling discards pixels and, done with good resampling, keeps images crisp. Upscaling cannot invent detail: enlarging 800 px to 2400 px yields softness, because the missing information simply does not exist in the file. The practical rule is to start from the largest original available and only ever scale down. Aspect ratio is the second rule: lock it. A 4:3 photo forced into a 16:9 box either distorts (squashed faces) or needs cropping... and deliberate cropping always beats accidental stretching.

Target sizes that cover most real needs

  • Full-width web hero: 1920 px wide (2560 for high-DPI audiences).
  • Content images in articles: 800-1200 px wide is plenty.
  • Open Graph / social sharing card: 1200 x 630.
  • Instagram: 1080 x 1080 square or 1080 x 1350 portrait. YouTube thumbnail: 1280 x 720.
  • Email signatures and avatars: 200-400 px... mail clients hate megapixel logos.

Resolution vs the 72 DPI myth

For screens, only pixel dimensions matter; the DPI value stored in a file is ignored by browsers entirely. DPI becomes real only in print: a 10 x 15 cm print at 300 DPI needs roughly 1200 x 1800 px. The related screen-era concept is device pixel ratio... a "400 px" image on a Retina display is actually drawn from 800 physical pixels, which is why serving 2x assets (or srcset variants) keeps photos sharp on modern phones.

File size follows area, not width

The non-obvious arithmetic of resizing: halving both dimensions quarters the pixel count, because pixels scale with area. A 4000 x 3000 photo holds 12 million pixels; at 2000 x 1500 it holds 3 million... which is why a modest-sounding reduction to 50% width typically cuts file size by 70-75% even before compression settings enter the picture. The same math runs the other direction as a warning: requesting a "slightly larger" 150% upscale demands 2.25x the pixel data, all of it invented by interpolation. When a target file size matters more than exact dimensions, resizing is the heavyweight lever and quality settings are the fine adjustment... in that order.

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