How to Convert Images Between PNG, JPG and WebP Without Uploading Them
Learn how to re-encode an image to WebP, PNG or JPG with the quality slider, read the estimated output size and download the result from the browser.
Image Format Converter
Introduction
Different destinations want different image formats: WebP for web pages, PNG for transparency and JPG for photo uploads with strict file type rules. The Image Format Converter redraws a PNG, JPG or WebP file onto a canvas and re-encodes it in the chosen format at the quality you set. Processing happens entirely in the browser through the canvas API, so the file stays on your device.
Step-by-Step Instructions
- Click Click to Upload Image and choose a PNG, JPG or WebP file; the name and original size in KB appear in the drop zone.
- Select a Target Export Format button: WEBP, PNG or JPG.
- Drag the Export Quality slider between 10 and 100 for WebP or JPG; the slider is hidden for PNG because PNG is lossless.
- Click Convert Image to start the re-encode and wait for the Conversion Complete badge with the estimated output size.
- Click Download Converted Image to save converted_image with the matching extension.
Key Use Cases
- Web Delivery: Re-encode a JPG photo as WebP at 80 percent quality to cut page weight.
- Form Uploads: Turn a WebP screenshot into JPG for a portal that only accepts JPEG files.
- Transparency Fix: Convert a WebP logo to PNG when a CMS needs a PNG with an alpha channel.
Frequently Asked Questions
What happens to transparent areas when converting to JPG?
JPG has no alpha channel, so the tool fills the canvas with white before drawing the image. Transparent pixels therefore become white in the JPG output. Converting to PNG or WebP keeps the transparency.
Can it convert AVIF or HEIC files?
The file picker is limited to PNG, JPEG and WebP input, and the output buttons offer WebP, PNG and JPG only. The converter relies on the browser's canvas encoder, so support for other formats depends on what the browser can decode and encode, and those formats are not offered in the interface.
How accurate is the output size shown after conversion?
The size is estimated from the length of the Base64 data URL the canvas produces, scaled by 3/4 to approximate the binary byte count. It is close to the final file size but can differ by a few bytes. The dimensions of the output always match the original image.