Image Resizer
Resize images in your browser — no upload.
Resizing for blog posts, avatars and thumbnails usually means uploading to some random site — here it happens on your device.
How to use
- Choose an image — it loads locally, never uploads.
- Enter new dimensions (aspect ratio locks by default).
- Click to resize and download the PNG.
About this tool
Aspect-ratio lock prevents squished images; unlock it for exact dimensions.
Your photos never leave your browser.
How it works
Resizing changes pixel dimensions: a 4000×3000 photo scaled to 1000×750 keeps one-sixteenth of its pixels. The aspect ratio (width ÷ height) should stay constant unless you mean to stretch — a 4:3 photo forced into 16:9 turns circles into ovals.
Downscaling discards detail, and the algorithm matters. Browsers use bicubic/Lanczos-class interpolation through the canvas API, which blends neighboring pixels smoothly — far cleaner than dropping every Nth pixel (nearest-neighbor), which leaves jagged edges.
Upscaling cannot invent detail: stretching 500 px to 2000 px just spreads the same information thinner. Scale down freely for the web; avoid enlarging past roughly 2× except for vector-like graphics.
Worked examples
A blog hero image: Your camera produces 6000×4000 (24 MP, often 8+ MB). Resize to 1600×1067 for the article header — it loads an order of magnitude faster, and no reader's screen displays more than that anyway.
Keeping proportions: Lock the aspect ratio, set the width to 800, and the height follows on its own (600 for a 4:3 photo) — no more stretched faces.
Quick reference
| Use | Suggested width |
|---|---|
| Blog article images | 1200–1600 px |
| Full-width hero / banner | 1920–2560 px |
| Thumbnails, avatars | 300–600 px |
| Email newsletters | 600 px max |
Frequently asked questions
What formats are supported?
JPG, PNG, WebP and GIF (first frame) for input; output is PNG.
Is there a size limit?
Browser memory is the only limit — typical photos are fine.
Are my photos uploaded?
No — 100% local processing.
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