Free Online Image Resizer
Resize JPG, PNG and WebP images by width and height. Keep the original aspect ratio, preview the result and download the resized image without uploading it to a server.
Choose an image to see its original dimensions.
Resize an image online without uploading it
This free image resizer changes image width and height directly in your browser. It is useful for website images, profile photos, online forms, social media posts, thumbnails, product images and email attachments.
Supported image formats
- JPG and JPEG
- PNG
- WebP
How to resize an image
- Select a JPG, PNG or WebP image.
- Enter the required width or height.
- Keep aspect ratio enabled to prevent stretching.
- Choose the output format and quality.
- Resize, preview and download the new image.
Frequently asked questions
Are my images uploaded?
No. The image is processed locally inside your browser.
How do I resize without distortion?
Keep the aspect ratio option enabled and change only one dimension.
Which format gives the smallest file?
WebP often produces smaller files for web use, while JPG works well for photos and PNG is useful when transparency is needed.
Resize by dimensions without accidentally stretching the image
Width and height control the number of pixels in the output. When the aspect ratio is locked, changing one dimension updates the other proportionally and prevents faces, circles and other objects from becoming unnaturally wide or tall.
Downscaling is safer than enlarging
Reducing dimensions can preserve a clean-looking image while cutting file size. Enlarging a small source cannot recreate detail that was never captured, so the result may look soft or pixelated even if the new dimensions are larger.
Choose dimensions for the destination
A website thumbnail, profile image, email attachment and print photo need different sizes. Check the destination's recommended pixel dimensions first instead of guessing. If there is also a file-size limit, resize first and compress afterward.
Keep the original
Save an untouched copy before resizing. That gives you a high-quality source if you later need another aspect ratio, a larger export or a different format.
What the Canvas resampling step actually does
When you resize an image, the browser decodes the selected file into an image bitmap and creates a Canvas with the requested output width and height. The tool then draws the source bitmap into that new pixel grid with drawImage(). When the destination contains fewer pixels, the browser must resample multiple source pixels into a smaller representation; when the destination is larger, it has to interpolate new pixel positions from the detail already present.
Why enlargement cannot restore missing detail
Changing a 600 × 400 image to 2400 × 1600 creates more pixels, but it does not recreate information that the camera or original file never captured. Interpolation can make edges look smoother, yet fine hair, text and texture may still appear soft. For that reason, resizing down is usually predictable, while aggressive enlargement should be treated as a display-size change rather than true detail recovery.
JPEG, PNG and WebP behave differently
The final Canvas is encoded with toDataURL() using the selected output format. The quality slider is meaningful for lossy encoders such as JPEG and WebP, but PNG is lossless and browsers generally ignore the numeric quality hint for PNG output. When JPEG is selected, this implementation first paints the Canvas white; transparent pixels are therefore flattened onto white because JPEG has no alpha channel. PNG or WebP should be used when transparency needs to be retained.
Metadata and memory considerations
Canvas export creates a newly encoded image and this implementation does not copy the source file's EXIF or other metadata into the new file. That can be useful when a lightweight web image is the goal, but it also means camera metadata should not be expected in the download. Very large output dimensions can consume substantial memory because Canvas stores an uncompressed pixel buffer internally, so choosing dimensions appropriate to the destination is safer than generating unnecessarily huge images.