Image Resizer
Resize photos to exact pixel dimensions with a live aspect-ratio lock — and see the before/after file sizes before you download. All inside your browser.
Resize an image
Nothing leaves your deviceChoose an image above — set the dimensions, then compare both file sizes here before downloading.
How to use this image resizer
- Pick an image. Drag a JPG, PNG or WebP file onto the dropzone, or click to browse. Its original dimensions fill the width and height boxes.
- Enter new dimensions. With the aspect-ratio lock on, changing one box updates the other automatically. Switch the lock off for exact independent sizes.
- Press Resize image. The result shows the original and resized versions side by side with their exact file sizes and the percentage change.
- Download to save the new file, or change the numbers and resize again — the same source image is reused, so you can try several sizes quickly.
Useful information
Resizing is the most reliable way to hit a target: an upload slot with fixed pixels, an avatar, a header image, a document figure. Done in a browser canvas, it needs no software install and no upload.
Shrinking vs enlarging
When you shrink, the tool averages groups of pixels into one, which keeps edges clean and detail tight. When you enlarge, the browser interpolates — it guesses the in-between pixels. That's fine for small bumps (a thumbnail to a preview), but pushing a photo far past its native size gives a soft, blocky result no tool can fully repair.
Dimensions vs file size
Pixel dimensions drive file size more than anything else: halving both sides cuts the pixel count to a quarter. If you need a smaller file at full size, that's compression's job — pair this with the Image Compressor for the quality slider.
Format stays put
The resized file keeps your input's format: JPG stays JPG (re-encoded at high quality), PNG stays PNG (lossless), WebP stays WebP. Transparency in PNG and WebP survives resizing. Need a format change instead? Use JPG to PNG or PNG to JPG.
Privacy: the image is read, scaled and encoded entirely on your device. There is no upload step at all.
Frequently asked questions
Which image formats can I resize?
JPG, PNG and WebP. The output keeps the same format as the input. GIF and SVG files are rejected because re-encoding them would lose animation or vector quality.
Does resizing reduce image quality?
Shrinking uses high-quality smoothing and looks crisp in practice. Enlarging cannot invent detail — a photo blown past its original size will look softer, so scale up only when you must.
How does the aspect-ratio lock work?
With the lock on (the default), editing the width automatically updates the height — and vice versa — so proportions never change. Turn it off to enter exact independent dimensions, for example when matching a fixed upload slot.
Will the resized file be smaller?
Usually yes when shrinking, since fewer pixels mean less data. The comparison shows the exact before and after bytes for your own file before you download — if the result is somehow larger, the tool says so plainly.
Are my images uploaded to a server?
No. Resizing happens on an off-screen canvas inside your browser tab. The file never leaves your device — the tool works with the internet disconnected.