Resize guide
Change pixel dimensions while controlling proportions
Image Resizer decodes one JPG, PNG or still WebP image, resamples it to the width and height you enter, and re-encodes it in the original format. Keep aspect ratio enabled for proportional resizing. Disable it only when an exact non-proportional canvas is required and stretching is acceptable.
How to resize an image
1. Add an image
Choose one JPG, PNG or WebP. The original pixel width and height fill the controls after decoding.
2. Set dimensions
With aspect ratio on, edit one side and let the other update. Turn it off to enter both sides independently.
3. Inspect the download
Resize, compare the reported dimensions and size, then check sharp edges, small text and transparency before replacing the original.
Practical uses
Prepare a smaller website image, fit a document layout, create email-friendly dimensions or normalize several assets one at a time.
Private local processing
The source is decoded into browser canvas memory and resampled with a browser-side image library. FiloTool does not receive the image bytes.
Supported formats
JPG/JPEG, PNG and still WebP input; output keeps the input format. JPG uses lossy re-encoding, PNG remains PNG and WebP remains WebP.
Limits and tradeoffs
Width and height must each be at least one pixel. The implementation has no fixed maximum dimension, but browser canvas and memory limits vary by device. Enlarging does not recreate missing detail.
A practical sizing example
For a 2400 × 1600 photograph needed at 1200 pixels wide, leave aspect ratio enabled and enter 1200 for width. The calculated height should be 800. Entering 1200 × 1200 with aspect ratio disabled would stretch the same photograph into a square; use Image Cropper instead when a square crop is the intended result.
Troubleshooting resize output
The image looks stretched
Reset, enable aspect ratio and change only one dimension. Crop when the destination shape differs from the source.
The download is larger
Dimensions and file size are different properties. Re-encoding can increase size; use Image Compressor after choosing the correct dimensions.
Small text looks soft
Avoid enlarging a low-resolution source. For reduction, compare at the final display size and keep the original available.
The browser cannot finish
Very large input or output canvases can exceed device memory. Choose smaller dimensions, close other large tabs or try a desktop device.
Choose dimensions and file size separately
The image resizing guide explains pixels versus bytes, why aspect ratio matters more than an exact pixel count, and why fewer pixels does not always mean a smaller file. Verify current platform requirements at the source before publishing.
Image Resizer questions
How do I resize without stretching the image?
Keep the aspect-ratio switch enabled and change either width or height. FiloTool calculates the other dimension from the original proportions.
Does resizing reduce file size?
Smaller pixel dimensions often reduce file size, but it is not guaranteed because the image is re-encoded. Use Image Compressor when a specific size-versus-quality adjustment is the main goal.
Can resizing improve a small blurry image?
It can create more pixels, but it cannot restore detail that is absent from the source. Image Upscaler offers enlargement controls, but it also cannot promise recovered detail.
Which formats does Image Resizer support?
The page accepts one JPG/JPEG, PNG or still WebP image and writes the result in the same format as the source.
What happens to transparency and metadata?
PNG and WebP transparency can remain in the decoded pixels. The canvas re-encoding pipeline does not reliably preserve EXIF, GPS, ICC or other source metadata.
Are images uploaded for resizing?
No. Decoding, resampling, re-encoding and download preparation run in your browser on the current device.