Does this crop the image to fit the new ratio?

No, it stretches instead of cropping. The full original content is preserved, but it's scaled non-uniformly (a different factor for width versus height) to reach the target proportions, which can distort the image rather than cut any of it away.

Why does the width stay the same?

The tool keeps the original width fixed and only recalculates the height needed to satisfy the requested ratio, giving a predictable, easy-to-reason-about result rather than resizing both dimensions simultaneously.

How is this different from the resizer?

The resizer takes exact target width and height values directly. This tool instead takes a target ratio (like 16:9) and derives the matching height automatically from the image's existing width.

Will my image look stretched or squashed?

If the target ratio differs meaningfully from the original, yes, visibly. This tool intentionally distorts proportions to hit an exact target ratio; if you want to avoid distortion, crop or pad to the new ratio instead.

PNG Aspect Ratio Changer - Restretch an Image's Proportions

Overview

Introduction

This tool restretches a PNG to a new aspect ratio, entirely in your browser, by scaling it non-uniformly to hit an exact target proportion.

It's useful when a specific width:height ratio matters more than preserving the original visual proportions exactly.

What Is PNG Aspect Ratio Changer?

A client-side aspect-ratio tool that reads an uploaded PNG's pixel data and computes a new height (keeping the original width) that satisfies a target ratio you specify, like 16:9 or 4:3.

It builds on the same shared nearest-neighbor resampling helper the resizer tool uses, just with the target dimensions derived from a ratio instead of entered directly.

How PNG Aspect Ratio Changer Works

The tool keeps the source image's width unchanged and computes a new height as width times (targetRatioHeight / targetRatioWidth), rounding to the nearest whole pixel.

It then resamples the image to those new dimensions using nearest-neighbor interpolation, which stretches or compresses the content vertically to fit.

When To Use PNG Aspect Ratio Changer

Use it when a platform or template requires a specific aspect ratio (like a 16:9 banner or a 1:1 square thumbnail) and stretching to fit is acceptable.

It's also useful for quickly previewing how an image would look distorted to a different ratio before deciding whether to crop or pad instead.

Often used alongside PNG Resizer, PNG Canvas Size Changer and PNG Cropper.

Features

Advantages

Runs entirely client-side; the uploaded image is never sent to a server.
Directly targets a specific ratio rather than requiring you to calculate exact pixel dimensions yourself.
Reuses the same tested resampling helper as the resizer tool.

Limitations

Always stretches rather than crops or pads, which can visibly distort the image if the target ratio differs significantly from the original.
Only adjusts height relative to a fixed width; it can't hold height fixed and adjust width instead.

Examples

Stretch a landscape photo to square

Input

A 1200x600 PNG (2:1), target ratio 1:1

Output

A 1200x1200 PNG with the original content stretched taller to fill the square

The width stays at 1200 and the height is recalculated to 1200 to satisfy the 1:1 target ratio, visibly stretching the content vertically.

Match a 16:9 banner requirement

Input

A 800x800 PNG (1:1), target ratio 16:9

Output

An 800x450 PNG with the original content compressed vertically

Since 800 * (9/16) = 450, the height shrinks to 450 to satisfy the 16:9 target ratio.

Best Practices & Notes

Best Practices

If distortion is unacceptable for your use case, use the cropper or canvas size changer instead to reach a target ratio without stretching.
Preview the result before downloading, since the visual distortion at extreme ratio changes can be significant.

Developer Notes

The lib function computes the new height from the target ratio and the source width, then delegates the actual resampling to the shared resizeNearest helper, the same one png-resizer.ts wraps, so both tools share identical resampling behavior with different dimension-calculation strategies.

PNG Aspect Ratio Changer Use Cases

Matching a platform's required banner or thumbnail aspect ratio
Previewing how an image would look distorted to a different proportion
Quickly converting a landscape image toward a square or portrait ratio

Common Mistakes

Expecting the image to be cropped rather than stretched to reach the new ratio.
Not accounting for how much visual distortion a large ratio change introduces before committing to the result.

Tips

For a ratio change without any stretching distortion, use the canvas size changer to pad instead, or the cropper to crop instead.
Try a target ratio close to the original first to judge how sensitive the image is to distortion before making a dramatic ratio change.

PNG Aspect Ratio Changer