Image Resizer
Resize a JPG, PNG, or WebP by pixels or percentage in your browser. Lock the aspect ratio, preview the result, and keep the original file format.
How to use Image Resizer
- Choose a still JPG, PNG, or WebP image to see its original dimensions.
- Resize by pixels or percentage. The aspect ratio is locked by default when setting pixel dimensions.
- Select Resize image, review the result's dimensions and size, and download the new image.
What is Image Resizer?
Resizing changes an image's pixel width and height. With the aspect ratio locked, changing one dimension calculates the other from the original proportions and rounds it to a whole pixel. Percentage scaling changes both dimensions by the same factor. Unlocking the ratio allows independent width and height changes, which can stretch the picture. Enlarging an image does not recover detail that was absent from the original.
- Pixel dimensions or percentage scaling
- Aspect ratio lock enabled by default
- Original JPG, PNG, or WebP format retained
- Result dimensions and downloadable preview
Supported images and limits
Choose one still JPG, PNG, or WebP image at a time. Each file can be up to 20 MiB, with no more than 25 million pixels and no side longer than 8192 pixels. Animated PNG and WebP files are rejected, as are GIF, SVG, HEIC, and other unsupported formats. Available memory and export support can impose additional limits on your browser or device.
Local processing and exported files
Your image is read and processed on this device. ADEMN does not upload it, store an image history, or include its contents, filename, or dimensions in tool analytics. Replacing the image, resetting the tool, or leaving the page releases the workspace's image resources; downloaded files remain wherever you saved them.
The tool creates a new image from the decoded pixels. Photos are decoded using their stored orientation, and the original EXIF metadata is not copied into the result. Encoding, color handling, and output size can vary by browser. JPG output fills transparent regions with white; PNG and WebP output preserve transparency.
A practical example
Original: 1600 × 1200 px New width: 800 px · Aspect ratio locked
800 × 600 px The original file format is retained.
Frequently asked questions
How is the second dimension calculated?
With the ratio locked, it is calculated from the original width-to-height proportion and rounded to the nearest whole pixel, with a minimum of one pixel. At very small sizes, exact proportions may not be possible.
Can I resize by a percentage?
Yes. For example, 50% makes each side half as long, giving one quarter of the original pixel count. A value above 100% enlarges the image within the tool's dimension limits.
Does resizing change the file format?
No. This tool keeps JPG, PNG, or WebP output in the source format. JPG and WebP are re-encoded with a default quality of 90%, which you can adjust. PNG uses lossless encoding of the processed pixels.
Will a smaller image always have a smaller file size?
Not necessarily. File size also depends on the original encoding, metadata, output quality, and image content. The tool shows the actual size after processing rather than estimating a guaranteed reduction.