Resize Image

Change width/height, keep aspect ratio

How it works

Resize Image — Change width/height, keep aspect ratio. All processing happens in your browser — no upload, no signup, no email required. Free forever.

Last updated: 2026-05-06

Editor's note

Aspect ratio errors are silent and cumulative — that is the whole story of this tool. A logo squeezed 4% looks "off" to every visitor on your site and not one of them can tell you why. Our own marketing page shipped for two weeks with a hero portrait stretched to fit a 16:9 container before someone outside the team mentioned the model looked unusually wide. Nobody on the team had caught it because we had all seen the unstretched version first; our eyes were already calibrated to the wrong thing.

So the aspect-lock toggle is locked by default and the unlock is a deliberate motion, not a casual one. We considered hiding the unlock entirely and decided that was paternalistic — there are legitimate reasons to stretch, like normalising a column to a fixed banner shape. But it should be a conscious choice, not the path of least resistance, because the cost of getting it wrong is invisible until it is too late to fix without redoing the export.

About Resize Image

Image Resize changes the pixel dimensions of an image — make it smaller for the web, fit a strict marketplace size, or generate retina variants. Most cameras and phones produce 4000–6000 px wide files, but a blog hero image rarely needs more than 1600 px and a thumbnail needs 400 px. Resizing first, then compressing, is the fastest way to shed weight without losing visible quality.

Marketers use it to hit Instagram's 1080 × 1080, LinkedIn's 1200 × 627, or Pinterest's 1000 × 1500. Developers batch-resize hero images before deploying. E-commerce teams normalise product photos to a uniform size. The tool keeps aspect ratio locked by default so you don't end up with stretched faces.

All resampling happens in the browser, so private images stay on your device.

How to use Resize Image

Drop your image or pick it from disk. The current dimensions appear next to the preview.
Type a new width or height — the locked aspect ratio fills the other field automatically.
Tap the lock icon if you want to stretch to exact non-proportional dimensions (rarely a good idea).
Optionally pick a preset (HD 1080, 4K, square 1080, etc.) to skip manual entry.
Click Download to save the resized image. The output keeps the input format.

Common use cases

Down-sizing 24-megapixel DSLR photos to 1600 px wide blog headers.
Producing a 1200 × 630 OG image from a square portrait crop.
Resizing screenshots to a uniform width before pasting them into product documentation.
Generating retina @2x assets from a 1024 px master for a mobile app.
Shrinking a profile photo to fit a forum's strict 200 × 200 avatar limit.

Tips & common mistakes

Always resize down, not up. Browsers blur scaled-up bitmaps; for true upscaling use a dedicated AI upscaler.
Keep aspect ratio locked unless you really need a stretched output — distorted product shots are an instant trust killer on a storefront.
Resizing first, then compressing, gives smaller files than compressing first.
If a marketplace asks for an exact pixel size, crop first (use Image Crop) and then resize, otherwise content gets squeezed.

Frequently asked questions

Can I lock the aspect ratio?

Yes. The lock icon between Width and Height keeps proportions when you change either dimension.

What format does the output have?

Same as the input. Use Image Convert separately to change format.

What about quality at large sizes?

Browsers use bilinear scaling by default. Going larger than the original will blur the image — for true upscaling try a dedicated AI upscaler.

What resampling algorithm is used?

Browsers use bilinear interpolation by default, which produces smooth results for downscaling. For best quality on big jumps (e.g. 4000 → 400 px), the result is excellent. Upscaling will inevitably look soft because no algorithm can invent detail that wasn't captured.

Will resize preserve transparency?

Yes for PNG and WebP. The alpha channel travels through the canvas pipeline untouched. JPG outputs keep their original (non-transparent) appearance.

Can I batch resize a whole folder to the same width?

Currently the workflow is one image at a time so you can verify each output. For pure batch jobs to a fixed dimension, the roadmap includes a folder mode.

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