Image tool
Image Resizer
Scale images to an exact width and height, a common preset or a percentage, keep each image’s aspect ratio, and download the batch as JPEG, PNG or WebP.
Resize images
Up to 20 files · one at a time
Task presets set an exact width and height; screen sizes keep each image’s own height.
PNG ignores the quality setting. JPEG fills transparent areas with white. Enlarging an image cannot add detail that was never captured.
Settings changed — resize again to apply them.
Images
Nothing queued yet
Your resized images will appear here.
Add a few files to set the size, then download the results.Files are processed sequentially to keep memory use predictable.
How it works
Add up to 20 JPEG, PNG or WebP images and choose a pixel size, a preset or a percentage.
Lock the aspect ratio, or enter width and height independently, then start the batch.
Review the new dimensions and file size for each image and adjust the settings if needed.
Download images one by one or take the whole batch as a ZIP.
Frequently asked questions
Will resizing improve image quality?
No. Enlarging adds pixels but cannot recover detail that was not in the original, and aggressive upscaling can look soft or blocky. Downscaling discards pixels and can make an image look cleaner at a smaller size, but it does not restore lost detail.
Which formats are supported?
JPEG, PNG and WebP input are supported, with the same output choices. AVIF and HEIC are not supported. PNG ignores the quality setting, and JPEG turns transparent areas white; use PNG or WebP when you need transparency.
Can I resize a whole batch to one size?
Yes. One size, preset or percentage is applied across the batch, and each image can keep its own aspect ratio. If you force both width and height, images with a different shape may be stretched.
What are the size limits?
Up to 20 images per batch, about 60 megapixels per image, and a 12,000 px longest side. Scale can be set from 1% to 400%, and a ZIP download is capped at 512 MB.
Are my images uploaded?
No. Resizing happens in your browser and the images are not sent to Ontool. There is no account or server copy, but a very large batch can be limited by your device’s memory.
Does resizing change the print size or DPI?
It changes pixel dimensions, not the physical print size by itself. Check the pixel dimensions your printer or publisher requires, and set the DPI in the destination app if you need a specific print size.