Lossless Image Resizer

How it works

This page changes pixel dimensions in your tab. It is not a “make the file smaller” compressor and not a TinyPNG / Adobe Express clone. Drop a photo, pick a rule, and download the result. Decode, resample, and encode stay in this browser.

1. Pick a rule — Max side fits the long edge (default 1920px, typical web/blog width). Width or Height lock one axis. Scale (%) multiplies both sides. Last rule and value stay in this browser.
2. Aspect ratio — On width or height, keep the other side proportional, or unlock it to stretch. Max-side and percent always keep the original ratio.
3. Output format — Auto (lossless) keeps PNG or WebP as-is and writes JPEG as PNG so you do not add another lossy pass. Force PNG or WebP when you need a specific type.
4. Compare & download — Original and resized sit side by side with pixel size and bytes. Copy the new width×height, or download name-1920x1080.png.

A 4000×3000 camera shot at max-side 1920 becomes 1920×1440. A 800×600 screenshot at 50% becomes 400×300. If the long edge is already under the cap, pixels stay the same.

This is not “resize image to 100KB” (byte cap) and not a DPI / print-inch planner. Those are other pages. Close the tab and the object URLs are revoked.

FAQ

Is this lossless?

PNG and WebP are written without a JPEG-style quality slider (WebP uses quality 1). JPEG sources are decoded once, then saved as PNG in Auto so you do not recompress JPEG. Resampling still changes pixels — a 4× shrink cannot invent detail.

JPEG, PNG, WebP, GIF?

Yes. GIF is decoded as a still frame (first frame), not an animated GIF editor.

Do you upload my photo?

No. createImageBitmap and canvas run locally. There is no account and no server store.

Why not iLoveIMG / TinyPNG / Photoshop?

Those products sit on the saturated “resize image” head. This page only does high-quality browser resampling with lossless output formats and a before/after pair — no signup, no batch cloud queue.