Image Resizer & Converter
Resize images and convert between PNG, JPEG and WebP entirely in your browser. Your image is never uploaded.
Pure browser JavaScript (HTML canvas) — no upload.
How to use this tool
- Choose an image.
- Set a new width (height keeps the aspect ratio).
- Pick a format and Download.
Resize images and convert between PNG, JPEG and WebP entirely in your browser. Your image is never uploaded.
How it works
This tool lets you resize images and convert between PNG, JPEG, and WebP formats entirely inside your browser. Your image is never uploaded to a server, so there are no privacy concerns and no file size limits imposed by an upload cap.
Drop or select an image file, set the target width and/or height in pixels, choose whether to maintain the aspect ratio, and select the output format. The tool uses the browser's Canvas API to redraw the image at the new dimensions and encode it in the chosen format.
Typical uses include reducing image file sizes before embedding them in a website, converting PNG screenshots to space-saving WebP or JPEG, and quickly generating thumbnails without installing desktop software.
JPEG and WebP outputs include a quality slider so you can balance file size against visual fidelity. PNG output is always lossless.
Worked example
Compress a PNG screenshot to a smaller WebP for a web page
- Click Choose File and select your PNG screenshot.
- Enter the target width (e.g. 800) and check Keep aspect ratio.
- Select WebP as the output format and set quality to 80.
- Click Resize / Convert.
- Download the resulting WebP file.
A WebP image at 800px wide with a file size typically 60-80% smaller than the original PNG.
Common mistakes to avoid
- Setting only one dimension without enabling Keep aspect ratio, which results in a stretched or squashed image.
- Choosing PNG output when you want a small file size — PNG is lossless and often larger than JPEG or WebP at similar quality.
- Trying to recover detail by enlarging a low-resolution source image — upscaling does not restore lost information.
Key terms
- WebP
- A modern image format developed by Google that provides superior compression for both lossless and lossy images compared to PNG and JPEG.
- Aspect ratio
- The proportional relationship between an image's width and height; maintaining it prevents the image from appearing stretched.
- Lossy compression
- A method that reduces file size by discarding some image data; used by JPEG and WebP at quality settings below 100.
Frequently asked questions
- Is my photo uploaded?
- No — resizing/conversion happens locally via the canvas API.