Resize Image Online — Change Pixel Dimensions for Free
Use the AllTools Image Resizer to change any photo or graphic to the exact pixel width and height you need. Enter custom dimensions or scale by percentage, with optional aspect-ratio lock to prevent stretching — all for free, no software to install.
Why use this Resize Image?
- Set exact width and height in pixels, or scale by percentage
- Lock aspect ratio to prevent distortion
- Supports JPG, PNG, WebP, and GIF
- Instant preview before you download
How to use the Resize Image
- Upload your image: Click 'Choose File' or drag your image into the upload area.
- Enter new dimensions: Type the target width and/or height in pixels, or choose a percentage scale.
- Lock aspect ratio (optional): Enable 'Keep aspect ratio' so the image scales proportionally without cropping.
- Download: Click 'Resize' and download your resized image in the same format.
Frequently Asked Questions
Can I resize an image without distorting it?
Yes — enable the aspect ratio lock and enter only one dimension (width or height). The tool will calculate the other side automatically to keep proportions correct.
What is the maximum output resolution I can set?
You can resize up to 10,000 × 10,000 pixels. Note that making an image larger than its original resolution will not add detail — it will only increase the canvas size.
Will resizing reduce the file size?
Making an image smaller in pixels usually reduces the file size significantly. Making it larger will increase file size. For maximum compression after resizing, run the result through the Image Compressor tool.
Can I resize a transparent PNG without filling the background?
Yes. PNG transparency is preserved during resizing, so your transparent areas remain fully transparent after the operation.
What formats are supported for output?
The resized image is saved in the same format as your original upload — JPG stays JPG, PNG stays PNG, and so on. To change format, use the Convert Image tool afterward.