GigAI Image Resizer scales JPG, PNG and WebP to exact pixel dimensions with Lanczos resampling (via pica), in your browser. Our benchmark took a 4000×3000 photo to 1600×1200 in 3.1 seconds, 3.4 MB down to 292 KB. Aspect-ratio lock, platform presets, no upload, no watermark, no account.
The GigAI Image Resizer scales your photos and graphics to any dimension you type, using the browser's high-quality canvas resampler for smooth, artefact-free results. Lock the aspect ratio to avoid stretching, or unlock it to force an exact frame. One-click presets cover the sizes that actually matter: Instagram square and story, a Facebook cover, an X/Twitter header, a YouTube thumbnail and a 1080p desktop wallpaper, so you never have to memorise pixel counts again. Everything runs locally in your tab: your image is never uploaded, and the result panel shows the original and new dimensions along with the exact scale factor applied.
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Drag a JPG, PNG or WebP onto the workspace, click to browse your files, or paste one directly from the clipboard.
Type an exact width and height, or click a social preset. Leave the aspect-ratio lock on to keep proportions intact.
Press Resize to resample the image locally. The before/after view shows the original and new dimensions side by side.
Save the resized image straight to your device. Need another size? Change the numbers and resize again, it's instant.
Type the precise pixel dimensions you need. The resizer renders to that size on the spot. No rounding surprises, no guesswork.
Keep the lock on and one field updates the other automatically, so your image scales in proportion and never looks squashed.
Snap to an Instagram post, story, Facebook cover, X header, YouTube thumbnail or 1080p wallpaper with a single click.
Both enlarging and shrinking use the canvas's high-quality smoothing, keeping edges clean and colors smooth at the new size.
The result panel spells out the old and new dimensions and the exact percentage you scaled by, so you know what happened.
Upload requirements differ everywhere, profile photos, banners, marketplace listings. Dial in the exact size a form demands and pass validation the first time.
The aspect lock does the maths for you, so portraits stay portraits and logos keep their shape instead of warping to fill a box.
Resizing happens in your browser with the canvas API. Your file is never sent anywhere, and even large images render in a moment.
It's a web page that works the same on a phone, tablet or laptop. No app, no plugin and no account to create first.
Numbers from running this exact tool against a fixed public sample, not marketing claims.
| Sample | the same 4000×3000 photograph |
|---|---|
| Result | 4000×3000 → 1600×1200, 3.4 MB → 292 KB, in 3.1 seconds |
| Worth knowing | Lanczos resampling via pica, with dimensions set to 1600 px wide. |
Measured on 2026-08-22 using Chromium on an Apple-silicon MacBook Air, everything in-browser. Re-measured with each release. The harness and samples are part of this site's test suite.
Boundaries stated plainly, with the right tool for each neighbouring job.
Accepts JPG, JPEG, PNG, WebP and GIF, and produces PNG, JPG and WebP, all processed locally in your browser.
See how the image resizer fits into a step-by-step journey with related tools.
Shrink JPG, PNG and WebP images without a visible quality drop. Set the quality yourself, or compress to an exact target size like 100 KB. Free, entirely in your browser.
Cut an image down to the exact part you want. Drag a crop box, snap to a ratio like 1:1 or 16:9, and export the trimmed area: free, private, in your browser.
Convert PNG and JPG images to WebP for smaller, faster-loading files, and turn WebP back into PNG or JPG when you need wider compatibility. Free and in-browser.
Convert JPG and JPEG images to lossless PNG in your browser, perfect for editing, transparency workflows and crisp graphics. Free, private, no upload.
Enlarge photos and graphics 2x or 4x in your browser with a real ESRGAN neural network that reconstructs sharp detail, free, private and nothing uploaded.
Convert iPhone HEIC photos to JPG (or PNG) in your browser, so they open everywhere. Free, private and instant. Nothing is uploaded.
The same engine runs behind the free API: send files, get signed download links back, and everything is deleted after the retention you choose. 1,000 tasks a month, no card.
Also runs as a task inside a job - chain it with the other engines. See the recipes.
curl -X POST https://api.gigai.tools/v1/jobs \
-H "Authorization: Bearer $GIGAI_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "tasks": {
"in": { "operation": "import/url", "url": "https://example.com/input.png" },
"work": { "operation": "resize-image", "input": ["in"] },
"out": { "operation": "export/url", "input": ["work"] }
} }'
# then poll until finished and follow the export URL:
curl https://api.gigai.tools/v1/jobs/JOB_ID/wait -H "Authorization: Bearer $GIGAI_API_KEY"Go deeper on the concepts behind the image resizer.
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image-toolsWhy resizing sometimes ruins an image and often doesn't, plus practical rules for keeping photos crisp when you scale them up or down.
Everything runs 100% in your browser. Your files are never uploaded to a server, never stored, and never seen by anyone but you.
Free, private and instant. Image Resizer runs right in your browser.