How to Convert Images to WebP and Compress Them Online

WebP is an image file format that supports both lossy and lossless compression, transparency and animation. Converting photos, screenshots or webcam snapshots from JPEG or PNG to WebP can reduce file size. The result depends on the source image and the settings you choose. This guide covers converting and compressing images with an online WebP tool and checking the result before you replace anything.

Before you start

• Find out where processing happens. Some online converters upload files to a server, and others process images inside the browser. The page layout does not show which one a tool uses, so read the tool's own description and privacy terms. If they do not say, assume your images are uploaded.
• Do not upload confidential or personal images to a service you have not checked. Use a local option instead, such as an image editor that can export WebP or the cwebp command-line encoder from Google's libwebp package.
• Work on copies and keep the original files. Lossy conversion discards data that cannot be recovered from the WebP file.
• Decide what the image needs: the final pixel dimensions, whether it has transparent areas, and whether its metadata, such as camera details or location, should be kept or removed.
• Confirm that the place where you will use the image accepts WebP. Current major browsers display it, but some upload forms, editors and older programs do not.

Step-by-step instructions

• 1. Copy the source images into a separate working folder.
• 2. Resize the image first if it is larger than it will ever be displayed. Keep the aspect ratio locked so the image is not stretched. Reducing pixel dimensions often saves more space than lowering quality alone.
• 3. Open the converter and add your files. Note any file size or batch limits that the tool states.
• 4. Select WebP as the output format.
• 5. Choose the compression mode. Lossy usually suits photos. Lossless, or lossy at a high quality setting, usually suits screenshots, logos, diagrams and images with text or sharp edges.
• 6. Set the quality if the tool offers it. Many tools use a 0–100 scale, but the same number can produce different results in different tools. Start with a moderately high value and lower it only after you have compared the output.
• 7. If the source has transparency, such as a PNG with a transparent background, make sure the tool keeps the alpha channel and does not fill it with a solid color.
• 8. Choose whether to keep or strip metadata, if the tool offers this. Stripping metadata can remove location data from camera and phone photos. Verify the result rather than relying on the option label.
• 9. Convert, download the results, and store them next to the untouched originals.

Setting names vary between tools. Some offer only a quality slider. Others add an effort or method option that trades encoding time for a smaller file. If you use cwebp locally, the -q option sets quality, -m sets the compression method, and -lossless switches to lossless mode. If a change gives a result you do not like, go back to the original file and convert again. Do not re-convert the WebP file.

Check the output

• Confirm the format. A .webp extension alone does not prove the file is WebP, so check the format in your operating system's file properties or an image viewer's info panel. On Linux, the file command reports WebP images as RIFF Web/P data.
• Compare file sizes. If the WebP is not smaller than the original, the conversion gained nothing. You can keep the original or try different settings.
• Compare the original and the WebP at 100% zoom. Look at text, thin lines, edges, smooth gradients for banding, skin tones, and fine colored detail. Lossy WebP stores color at reduced resolution, so small red or blue details and colored text can blur.
• Check that the pixel dimensions and aspect ratio match what you intended.
• For transparent images, view the result on both light and dark backgrounds to spot halos or filled-in areas.
• If privacy matters, inspect the metadata of the output file to confirm what was kept or removed.
• Open or upload the file in the actual place you will use it, and confirm it displays correctly there.

Common problems and next steps

• The WebP file is larger than the original: this can happen when you re-encode an already heavily compressed JPEG or use lossless mode on a photo. Try lossy mode, a lower quality, or smaller pixel dimensions, or keep the original format.
• Text looks soft or colors bleed around edges: raise the quality or use lossless mode, especially for screenshots and graphics.
• Transparent areas turned black or white: the tool flattened the alpha channel. Use a tool or mode that preserves transparency, then check the result again.
• The image appears rotated: some cameras record orientation in metadata. A converter that strips metadata without applying that rotation can produce a sideways image. Rotate the original so the pixels themselves are upright, then convert again.
• An animated GIF became a still image: WebP supports animation, but not every converter produces animated WebP. Check whether the tool supports animation, or use one that states it does.
• An app or website will not open or accept the file: that program may not support WebP. Use the original JPEG or PNG for that purpose.
• Quality keeps getting worse after edits: each lossy save discards more detail. Edit the original, then export to WebP once at the end.