How to Compress WebP Images Online

Before you start

A WebP file can already be smaller than an equivalent JPEG or PNG, but it may still need further size reduction for email, messaging, or a page that loads slowly. The process below uses an online image size reducer that works in a web browser, so no app installation is required. You only need the WebP file available on the device and permission to upload it to the chosen service. Because the file leaves the device during processing, avoid uploading private or sensitive images unless the service's data handling policy clearly matches what you require.

Step-by-step instructions

Open a browser-based image size reducer that lists WebP as a supported input or output format. If the tool supports multiple file formats, choose WebP rather than converting the image to another format before resizing.

Add the WebP image. Some tools have a drop zone; others provide an upload button. After the image loads, look for quality, compression, or resize controls.

Set the output size. A quality slider affects compression and file size, while pixel dimensions control how large the image appears. Keeping the aspect ratio locked prevents the image from being stretched when you change width or height.

If the image contains transparency, confirm that the output remains in a file format that supports it. WebP supports transparency, but converting to JPEG would fill transparent areas with a solid background.

Process the image and download the result. If the service offers a preview, compare it with the original at normal viewing size before saving the smaller file.

Check the output

Open the downloaded file and check edges, fine text, and areas with smooth gradients. These are the places where aggressive compression becomes visible first. Confirm the file size is smaller than the original and that the pixel dimensions are what you intended. If the image appears soft or shows blocky artifacts, repeat the process with a higher quality setting or less aggressive size reduction.

Common problems and next steps

If the output file is larger than the original, the image may already be heavily compressed. Reduce the pixel dimensions or lower the quality setting, then confirm the result is smaller. If transparency disappears, check whether the selected output format supports alpha channels. If the downloaded file cannot be opened, the download may be incomplete or the service may have changed the format; download again and verify the extension before use.