Convert to AVIF
AVIF is useful when compact files are a priority. Try it for photos and other web images, and allow a little more time for encoding. Compare the result with your original to find a quality setting you like.
FREE AVIF & WEBP IMAGE CONVERTER
Great images. Less weight.
Convert your images to AVIF or WebP, in just a whistle.
Private by design. Your files stay on your device.Drop your images here
Images, folders, or ZIPs. Add files, choose your settings, then convert.
PNG, JPEG, WebP, GIF, BMP & TIFF · ZIP archives welcome · Up to 15.0 MB per image
Your images 0
Your added images will appear here
A LIGHTER WAY TO WORK
A free image converter, right in your browser
Turn PNGs, JPEGs and other images into AVIF or WebP to save weight — or convert WebP back into PNG and JPEG when another app needs it. Resize and batch convert in one place, with your files staying on your device.
Add your images
Choose images, a folder or a ZIP. Review the queue and remove any files you do not need.
Make them your own
Pick an output format, adjust the quality, and keep the original dimensions or set a size limit.
Convert and download
Click Convert. Get one image directly, or download your batch together as a ZIP.
Which output format should I choose?
Convert to WebP
WebP is a practical choice for quick conversions and everyday web images. Try converting your PNG or JPEG to WebP, then compare the appearance and file size. Check that the app or platform you are using accepts your chosen format.
Convert to PNG or JPEG
Reach for these when something will not accept a modern format. JPEG is the smaller choice for photographs but has no transparency; PNG is lossless and keeps transparency, at a larger file size.
Want the technical details? Read the MDN image format guide.
Pages for a specific conversion
Each of these opens the same converter, already set to the conversion you need. Useful when you know exactly what you are starting with and want to finish with.
A few things you might be wondering
Which image formats can I convert?
Whistle reads PNG, JPEG (JPG), WebP, GIF, BMP and TIFF images and writes AVIF, WebP, JPEG, PNG, GIF, BMP or TIFF. That covers converting to the lighter modern formats and converting them back for apps that need one. You can add individual images, choose a folder, or drop a ZIP containing supported images. AVIF, HEIC and SVG input files are not currently supported.
Are my images uploaded or stored?
No. The conversion happens in your browser, on your device. Your selected files are not sent to our servers, and your originals are not changed. Whistle saves your theme, saved conversion preferences and analytics choice in your browser. If you allow analytics, Google Analytics uses cookies to measure visits and conversion results, including output format and file counts. Images and filenames are never included. You can change your choice using Analytics preferences when analytics is available.
Can I convert multiple images at once?
Yes. Add your files, remove any you do not want, and click Convert when you are ready. Multiple converted images download together as a ZIP. Each input image can be up to 15 MB. For batches over 30 images, previews are hidden to keep the page responsive; you can turn on individual previews.
How do I reduce image file size?
Choose AVIF or WebP, then adjust image quality and the longest side. Lower quality or smaller dimensions can reduce file size. Start with the default quality of 80%, inspect the downloaded image, and adjust to suit your needs. Results depend on the original image; conversion will not always make an already compressed file smaller. For the same reason, converting to PNG, BMP or TIFF usually produces larger files.
Can I keep the original image dimensions?
Yes. Select Original under Longest side before converting. It is the default when you choose PNG, JPEG, GIF, BMP or TIFF, so a format change never resizes your images by surprise. AVIF and WebP start with a 1024 pixel limit; you can choose a preset, enter a custom limit, or select Original. Resizing keeps the original proportions.
Can I convert WebP to PNG or JPG?
Yes. WebP is one of the formats Whistle reads, so you can convert it to PNG, JPG or any other output. Choose the format under Output format, or open the WebP to PNG or WebP to JPG page, which starts the converter already set up. WebP to PNG keeps transparency, while WebP to JPG usually gives the smaller file.
Is Whistle free to use?
Yes. You can convert, resize and download images without paying or creating an account. Conversion speed depends on your device, image size and settings. AVIF encoding can take longer, especially with a lower encoding speed setting.