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Image Resizer

Drop an image, type the width or height you want, and download the resized file — PNG, JPG, or WebP. The aspect ratio stays locked by default, so a 4000 × 3000 photo set to 1200 px wide becomes exactly 1200 × 900. Everything happens on a <canvas> in your browser: the picture is never uploaded, which matters when you're resizing a screenshot from a private dashboard, a product photo under embargo, or a scan of an ID. The result is a fresh file at the new pixel dimensions, not a CSS trick that ships the full-size image and shrinks it on screen.

Drop an image here or click to choose

Resized in your browser — the file never leaves your device. JPG, PNG, WebP, GIF, BMP.

How to use the image resizer

  1. Drop or choose an image — its real pixel dimensions and file size appear above the controls.
  2. Pick 'By pixels' and enter a width or height (the other side follows while 'Lock aspect ratio' is on), or pick 'By percent' to scale to, say, 50%.
  3. Choose an output format and, for JPG/WebP, a quality level. PNG stays lossless.
  4. Click Resize, check the preview and the new file size, then Download.

Resizing vs. resampling: what actually changes

"Resize" is overloaded. Three different operations hide behind the word, and confusing them is why images come out blurry or the wrong size:

  • Resampling (what this tool does): the browser recomputes every pixel for the new dimensions and writes a new file. A 4000-px-wide photo saved at 1200 px is genuinely 1200 pixels of data. This is what you want for the web, email, and uploads with size limits.
  • Display scaling: setting width="1200" in HTML or CSS leaves the 4000-px file untouched and just paints it smaller. The page still downloads every byte — the slow, bandwidth-wasting trap this tool avoids.
  • Changing DPI/PPI metadata: editing the "300 DPI" tag changes how big the image prints, not how many pixels it has. For screens, DPI is irrelevant; pixels are everything.

Common target sizes

You rarely need to invent dimensions. The destination usually dictates them:

UseTypical sizeNotes
Full-width blog image1200–2000 px wide2× for retina; let the CMS make smaller copies
Email / newsletter600 px wideThe classic email body width
Open Graph / social card1200 × 6301.91:1; crop first, then resize
Avatar / thumbnail200 × 200 or 400 × 400Square; use the cropper for a 1:1 first
Marketplace photo limit1600 px longest sideCheck the platform's stated max

When you have a fixed canvas like the 1200 × 630 social card, crop to that ratio before resizing — squeezing a 3:2 photo into 1.91:1 distorts faces. Pair this with the image cropper and the aspect ratio calculator.

Frequently asked questions

Is my image uploaded anywhere?

No. The file is read with the FileReader/Image APIs, redrawn on an HTML canvas at the new size, and exported with canvas.toBlob — all in your browser. You can switch off your network after the page loads and it still works. Nothing is sent to a server, so private screenshots, IDs, and embargoed assets stay on your machine.

Will resizing reduce the file size?

Almost always, when you shrink. Fewer pixels means less data: dropping a 4000 px photo to 1200 px removes about 91% of the pixels, and the file usually falls by a similar order of magnitude. The exact number depends on the format and quality you export at — the tool shows the before/after size and the percentage change after each resize.

Why does my image look blurry after resizing up?

Enlarging past the original can't invent detail that was never captured. Going from 600 px to 2000 px stretches existing pixels, so edges soften and JPEG artifacts get bigger. The tool warns when your target exceeds the source. For real upscaling you need AI super-resolution; a canvas can't reconstruct missing information.

Should I save as PNG, JPG, or WebP?

JPG for photographs (smallest files at good quality, no transparency). PNG for screenshots, logos, line art, and anything needing transparency — it's lossless but larger. WebP usually beats both: 25–35% smaller than JPG at similar quality, with transparency support, and every current browser reads it. If you're unsure and the image is a photo, try WebP first.

Does resizing keep transparency?

Yes, if you export to PNG or WebP, which support an alpha channel. JPG has no transparency, so this tool fills the background with white before drawing — otherwise transparent areas would turn black. Resize a transparent PNG to PNG or WebP to preserve the see-through areas.

What's the largest image I can resize?

It's limited by your device's memory, not a server. Very large canvases (this tool caps the output at 12,000 px per side) can exceed browser limits and fail silently, which is why there's a guard. In practice multi-megapixel phone photos resize instantly; truly huge panoramas may need a desktop with more RAM.

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