Lumagely
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Resize images

Resize photos by exact pixels or by percentage, with aspect ratio locked — across a whole batch, right in your browser.

  • No uploads — 100% on-device
  • Fast in-browser processing · WASM codecs
  • Unlimited files · up to 256MB each

Drop images here

or Browse files

Tip: paste images directly with Ctrl+V

HEIC · PNG · JPEG · WebP · AVIF · GIF · SVG

Whether you need a 1920px-wide banner or to halve every image in a folder, Lumagely resizes on-device using high-quality Lanczos scaling. Set pixels or a percentage, keep the aspect ratio, and apply it to the entire batch — no upload.

How to resize images

  1. 1Drop your images in — resize is already enabled.
  2. 2Enter a max width/height in pixels, or a scale percentage.
  3. 3Download each resized image, or the batch as a ZIP.

Good to know

  • Resizing uses Lanczos (via pica) for sharp, clean results.
  • Images are never upscaled — smaller originals are left as they are.
  • Resize pairs with compression and target file size for even smaller files.

Resize Image — questions

Can I resize many images at once?

Yes. The resize settings apply to the whole batch, and you can download everything as a ZIP.

Will resizing keep the aspect ratio?

Yes, aspect ratio is locked by default so images never look stretched. You can turn it off for an exact width and height.

Does it upscale small images?

No — to protect quality, images are only ever scaled down, never up.

Everything you can do

A complete image toolkit — compress, convert, resize, crop, rotate and watermark — all running privately in your browser.

  • Smart compression

    Shrink PNG, JPEG, WebP and AVIF with WebAssembly codecs — Smart Auto, lossy, near-lossless or fully lossless.

  • Target file size

    Set a limit in KB and Lumagely finds the best quality that fits — ideal for upload caps and email attachments.

  • Convert & HEIC to JPG

    Convert between PNG, JPEG, WebP and AVIF, turn iPhone HEIC photos into JPG, and modernize old GIFs.

  • Resize, crop & rotate

    Resize by pixels or percentage, crop to any aspect ratio, and rotate or flip — across the whole batch.

  • Batch watermark

    Stamp a text or logo watermark onto every image, with full control over position, size, opacity and margin.

  • Private & offline

    Everything runs on your device in Web Workers — no uploads, no sign-up, and it keeps working offline.

Supported formats

Compress, convert and optimize the formats the modern web runs on.

  • HEIC

    Convert iPhone HEIC photos to JPG, PNG, WebP or AVIF.

  • PNG

    Lossless compression with OxiPNG.

  • JPEG

    High-quality photos with MozJPEG.

  • WebP

    Smaller photos & graphics, lossy or lossless.

  • AVIF

    Next-gen format with the best compression for photos.

  • SVG

    Minify vectors, or trace raster images into SVG.

  • GIF

    Convert GIFs to modern, smaller formats.

Why Lumagely?

100% private

Your images are processed on your device and never uploaded to any server.

Fast & modern

WebAssembly codecs (MozJPEG, OxiPNG, libwebp, libavif) run at near-native speed in your browser.

Free & unlimited

No sign-up, no forced watermarks, no limits — optimize as many images as you like.

Browser-based vs. upload-based

Typical upload tools

  • Images are uploaded to a server
  • Sign-up or usage limits are common
  • Often split across separate tools
  • Privacy depends on the provider

Lumagely

  • Images stay on your device
  • No sign-up — unlimited files
  • Compress, convert, resize and social export in one place
  • Private by design — nothing leaves your browser

More image tools

One-tap tools for the most common image jobs — all free, all in your browser.