圖片調整大小工具

An image resizer that scales a photo to exact pixel dimensions in your browser and exports it as PNG, JPEG or WebP. Set the width and height you need, with an optional aspect-ratio lock so the image does not stretch.

Resizing to specific dimensions is one of those constant small tasks: fitting an avatar or profile picture, making a thumbnail, meeting a platform's required size, or getting a photo under an upload limit.

Because everything runs on your device, your photos are never uploaded to a server, which keeps personal and sensitive images private.

It runs locally with the Canvas API, redrawing the image at the new size. There is no server round-trip, so resizing is fast and your photos never leave your device, which matters for personal pictures, ID scans and anything private.

You can export to PNG for lossless output, or to JPEG or WebP with an adjustable quality that trades file size against detail. WebP usually gives the smallest file at a given quality, while JPEG is the universal choice for photos.

Keeping the aspect ratio locked changes width and height together so the picture is not distorted. Unlock it only when you deliberately want to stretch or squash to a specific shape.

Shrinking an image is generally clean and crisp. Enlarging it beyond its original size cannot invent detail that was never captured, so an upscaled image may look soft. For best results, start from the largest original you have.