How is this different from plain stretching or cropping?

Stretching touches every pixel: people get wider, circles become ovals, and anyone can see it. Cropping throws whole strips of content away, losing both composition and information. Content-aware scale does neither — it only removes the chains of pixels that carry the least information, so the subject keeps its proportions and the things at the edges are still there.

Why do I have to press a button when every other tool is instant?

Because this one is far more expensive. The other operations are one or two passes over the image (milliseconds), whereas seam carving recomputes the energy map and runs a dynamic program for every single seam. Measured: 0.8 s for 600×800 at −20%, 6 s for 1920×1080 at −10%. Following the slider would freeze the page for seconds every time you let go — with nothing on screen to say it was working. So you decide when.

Why are the edges a bit soft on large images?

Because anything over 900 pixels is scaled down to a 900-pixel long edge before the seams are computed, then scaled back to the size you asked for. Without that step a phone photo would take tens of seconds. It's a genuine trade between speed and sharpness, written here rather than left for you to discover. Images under 900 pixels skip it entirely and are carved at full resolution.

Which images does it do badly on?

Busy ones — a group photo, dense typography, a regular building façade. Seam carving needs low-energy regions to give way, and pictures like these barely have any, so the algorithm is forced into material that should have been kept; you get bent lines. For those, an ordinary crop is safer.

Content-aware scale: change the proportions without squashing people

Turn a landscape shot into a portrait one, or 16:9 into 4:3, without flattening the people in it.

or start a blank document

It solves one specific nuisance: a 16:9 photo has to fit a 4:3 slot. Cropping the sides throws content away; stretching makes people wider and circles oval — and both are obvious to anyone looking.

How it works. The algorithm gives every pixel an "energy" (its gradient — high at edges, low across flat areas), finds the top-to-bottom chain of pixels with the lowest total energy, and deletes that whole chain. Repeat, and what disappears is sky, wall and grass, while faces, text and building edges are left essentially untouched. The technique is called seam carving.

Key features

The subject keeps its shape; the background gives way

What gets deleted is the lowest-energy chain of pixels, so empty background goes first as the image narrows. High-gradient areas like faces and text are actively routed around.

It stretches outward too

Inserting seams instead of removing them widens the image: pixels are added where the picture is flattest rather than pulling the whole thing apart. Handy for turning a portrait shot into a banner.

You press a button; it doesn't follow the slider

The algorithm scans the whole image once per seam — measured at 6 seconds for 1920×1080 at −10%. So unlike the other tools it doesn't recompute as you drag. Set the width and height first, then press Run.

Images aren't uploaded

The whole computation finishes in your browser; no request carries image data. Open the network panel in your developer tools and check for yourself.

How to use

1
Drag your image in

JPG, PNG and WebP are all accepted, and Ctrl+V pastes from the clipboard.
2
Set width and height

Both sliders are percentages, 50%–150%. Changing just one is fine; leave the other at 100%.
3
Press Run

The page says so while it's working. The bigger the image and the larger the change, the longer the wait — that's the algorithm's own cost.
4
Compare the two, then download

Original on the left, result on the right, side by side. Not happy? Change a number and press again.

FAQ

How is this different from plain stretching or cropping?: Stretching touches every pixel: people get wider, circles become ovals, and anyone can see it. Cropping throws whole strips of content away, losing both composition and information. Content-aware scale does neither — it only removes the chains of pixels that carry the least information, so the subject keeps its proportions and the things at the edges are still there.
Why do I have to press a button when every other tool is instant?: Because this one is far more expensive. The other operations are one or two passes over the image (milliseconds), whereas seam carving recomputes the energy map and runs a dynamic program for every single seam. Measured: 0.8 s for 600×800 at −20%, 6 s for 1920×1080 at −10%. Following the slider would freeze the page for seconds every time you let go — with nothing on screen to say it was working. So you decide when.
Why are the edges a bit soft on large images?: Because anything over 900 pixels is scaled down to a 900-pixel long edge before the seams are computed, then scaled back to the size you asked for. Without that step a phone photo would take tens of seconds. It's a genuine trade between speed and sharpness, written here rather than left for you to discover. Images under 900 pixels skip it entirely and are carved at full resolution.
Which images does it do badly on?: Busy ones — a group photo, dense typography, a regular building façade. Seam carving needs low-energy regions to give way, and pictures like these barely have any, so the algorithm is forced into material that should have been kept; you get bent lines. For those, an ordinary crop is safer.

Try Content-aware scale: change the proportions without squashing people now

Runs fully in your browser · no install · no signup · images never uploaded