Image Resizer

How to use the Image Resizer

Drop in your image. The current dimensions appear in the width and height boxes.
Type a new width — the height follows automatically while the ratio is locked — or drag the percentage slider.
Press Resize, check the preview, and download.

Aspect ratio and why the lock matters

Aspect ratio is width divided by height. Change one dimension without the other and the image stretches — faces widen, circles become ovals. The lock keeps them proportional, which is right for almost every use.

Unlock it only when you deliberately need exact dimensions and accept the distortion, or when the source already matches the target ratio. If you need an exact ratio without stretching, crop rather than resize: the Image Cropper removes the excess instead of squashing it.

How the downscaling works

Shrinking an image to a fraction of its size in one step produces aliasing — jagged edges and shimmering detail — because most browsers sample too few source pixels per output pixel.

This tool steps down in halves instead, repeatedly halving the image until it is within one factor of two of the target, then doing the final resize. Each halving averages four pixels into one, which preserves detail far better. The difference is clearly visible on text and fine patterns.

Common target sizes

Use	Dimensions
Full-width hero image	1920 × 1080
Blog content image	1200 wide
Open Graph / social preview	1200 × 630
Square profile picture	1080 × 1080 or 400 × 400
Thumbnail	300–400 wide

For high-density screens, export at roughly twice the display size and let the browser scale it down — a 600-pixel column looks sharpest with a 1200-pixel image.

Frequently asked questions

Can I make a small image bigger?

You can, but it will look soft. Enlarging invents pixels by interpolating between existing ones; the detail was never captured. Beyond about 150% the softness becomes obvious.

Why does my file size barely change?

Format and quality matter as much as dimensions. If you resized but kept PNG at full quality, try JPG or WebP output, or use the Image Compressor.

How do I resize to an exact size without distortion?

Crop to the right ratio first, then resize. Cropping removes the excess rather than squashing it, which keeps everything in proportion.

Is there a size limit?

Files up to 25 MB and output up to 12,000 pixels on a side. Beyond that browsers commonly run out of canvas memory and fail silently.