By Daniel Rowles, lead trainer at Target Internet and author of Digital Branding (Kogan Page). Last updated: November 2026.
Squoosh is a free, open-source image compressor built by Google Chrome Labs that runs in your web browser at squoosh.app. You drop in an image, choose a format such as WebP, AVIF or MozJPEG, and compare the original and compressed versions side by side before downloading the smaller file.
This guide explains how to use Squoosh step by step, which format to choose for different types of image, whether it is safe and free, and what to use instead when you need to compress images in bulk. It is written for marketers and content teams who publish images on websites, not for developers.
Why image compression still matters for marketers
Image compression matters because images are usually the heaviest part of a web page, and heavy pages load slowly. Slow pages frustrate visitors, reduce conversions and can hold back search performance through Google's Core Web Vitals, particularly Largest Contentful Paint, which is often an image.
The good news is that compression is one of the easiest speed wins available. A photo straight from a phone or a stock library is often several megabytes, when the version a visitor actually needs is a few hundred kilobytes. Fixing that does not require a developer, a new CMS or a budget: it requires a few minutes with a tool like Squoosh before you upload.
At Target Internet we use Squoosh to get our article diagrams under 300KB before they go on the site. It has become a routine step in our publishing process, because it is quicker to compress an image once before upload than to diagnose a slow page later. If you want to understand how image weight fits into wider page experience, our Core Web Vitals course covers the metrics Google uses and how to improve each one.
How do you use Squoosh to compress an image?
You compress an image in Squoosh by opening the app, adding your image, choosing an output format and quality, checking the preview, and downloading the result. The whole process takes under a minute once you know where the settings are.
- Go to squoosh.app in Chrome, Edge, Firefox or Safari. Nothing needs to be installed.
- Drag your image onto the page, or use the link to select a file from your computer. You can also paste an image from your clipboard.
- In the panel at the bottom right, choose an output format from the Compress menu. MozJPEG, WebP and AVIF are the most useful for website images.
- Lower the quality slider gradually and watch the preview. Zoom in on fine detail such as faces, text and edges, because that is where over-compression shows first.
- Use the Resize option to reduce the image to the largest width it will actually be displayed at on your site.
- Check the file size and percentage saving shown under the panel, then click the download button.
The slider in the middle of the screen is what makes Squoosh useful. Drag it left and right to compare the original image with the compressed version, or set both sides to different formats to compare them with each other. This turns compression from guesswork into a visual decision: you can see exactly how far you can push the quality before the image looks worse.
Copy-and-paste checklist: "Before upload: resize to [display width]px, export as [WebP or AVIF], start at quality 75, zoom to 100% on faces and text, stop reducing quality at the first visible artefact, aim for under [300]KB."
Which image format should you choose in Squoosh?
For most website photos, WebP is the safest default and AVIF gives the smallest files. Use MozJPEG when an image must stay as a JPEG, OxiPNG for screenshots and graphics that need sharp edges, and treat JPEG XL as experimental because browser support is still incomplete.
| Format in Squoosh | Best for | Browser support (November 2026) | Typical saving |
|---|---|---|---|
| WebP | Photos and graphics, as a safe all-round default | About 97% of users | 25-34% smaller than JPEG; 26% smaller than PNG (lossless) |
| AVIF | Photos where the smallest file matters most | About 97% of users | Often more than 50% smaller than JPEG |
| MozJPEG | Photos that must stay as JPEG, for example for email or older systems | Universal | Smaller than a standard JPEG at similar quality |
| OxiPNG | Screenshots, logos and diagrams with text or flat colour | Universal | Lossless: no quality is lost |
| JPEG XL | Testing only | About 69% of users, partial in Safari | Not yet safe as your only format |
Google's own figures put WebP lossless images 26% smaller than PNGs and lossy WebP images 25-34% smaller than comparable JPEGs (Google for Developers). Google's web.dev team reports AVIF savings of more than 50% compared with JPEG, depending on the image and settings. Browser support figures are from Can I Use, November 2026: WebP is supported for around 97% of users, AVIF for around 97%, and JPEG XL for around 69%.
The practical rule is simple. If your CMS accepts WebP or AVIF, use one of them for photos. If it only accepts JPEG and PNG, use MozJPEG for photos and OxiPNG for graphics. Our diagrams at Target Internet contain text and flat colour, so they compress best as OxiPNG or lossless WebP, while photos go to WebP or AVIF.
Lossy or lossless compression?
Lossy compression makes files smaller by permanently discarding detail the eye is unlikely to notice. JPEG, MozJPEG and most WebP and AVIF settings are lossy. Lossless compression stores exactly the same image more efficiently, so nothing is lost, but the files are larger. PNG and OxiPNG are lossless.
Use lossy for photos and lossless for anything with text, sharp lines or a logo.
Squoosh also offers a Reduce palette option, which cuts the number of colours in an image. It works well for simple graphics and illustrations with a handful of colours, and makes little difference to photographs.
If you want to build these skills into a wider understanding of technical SEO and page experience, the Target Internet platform includes interactive courses such as user experience and SEO, accredited certification, over 400 episodes of the Digital Marketing Podcast, and monthly live masterclasses delivered by working practitioners.
Is Squoosh safe and free to use?
Squoosh is free and is considered safe because your images are processed on your own device rather than uploaded to a server. According to the project's GitHub documentation, the only data collected through Google Analytics is basic visit information, image sizes before and after compression, and installation details if you install Squoosh as an app.
That makes Squoosh a sensible choice for images you would not want to upload to a third-party service, such as unreleased product shots or client work. It is open source under Google Chrome Labs, so its code can be inspected publicly. After the first visit it also works offline, and it can be installed as a progressive web app from the browser.
The main limitation is not safety but scale: Squoosh is designed for one image at a time.
Can Squoosh compress images in bulk?
No: the Squoosh web app compresses one image at a time, and Google no longer maintains the command-line tool and Node library that once allowed batch processing. The npm package for the Squoosh CLI is marked as no longer maintained, and frameworks such as Astro have since removed their Squoosh image service in favour of alternatives.
If you need to compress many images, these options are more practical:
- An image optimisation plugin or setting in your CMS, which compresses images automatically on upload.
- An image CDN or hosting service that converts images to WebP or AVIF on the fly.
- Sharp, an actively maintained Node.js library, if a developer can script batch conversion for you.
- A community fork of the old Squoosh CLI, accepting that it is not supported by Google.
For most marketing teams, the best answer is a combination: let the CMS or CDN handle routine uploads, and use Squoosh for important images where you want to check the quality yourself, such as hero images, diagrams and anything above the fold.
How to build image compression into your workflow
The teams that keep their sites fast treat compression as a publishing step, not an occasional clean-up. Agree a target file size, a default format and a maximum width for each type of image, and make them part of the checklist anyone uses before publishing.
Then measure the result. Run your key pages through Google PageSpeed Insights before and after compressing their images, and check the Core Web Vitals report in Google Search Console for pages that are flagged as slow. If you are reviewing the tools in your SEO toolkit more broadly, our comparison of the best SEO tools covers the platforms that can audit image weight across a whole site.
We first reviewed Squoosh on The Digital Marketing Podcast shortly after Google launched it, and it remains one of the free tools we recommend most often in training. For more on the wider discipline, our SEO resources bring together our guides, courses and podcast episodes.
If you are ready to take a structured approach to building your digital marketing skills, explore Target Internet membership options and discover how the platform's interactive courses, benchmarking tools, podcast, accredited certification and live masterclasses can accelerate where you are heading next.
Frequently asked questions
Is Squoosh free?
Yes, Squoosh is completely free. There is no account, subscription or usage limit, and no watermark is added to your images. It is an open-source project from Google Chrome Labs, available at squoosh.app in any modern browser. You can also install it as a progressive web app, which lets you use it offline after your first visit.
Does Squoosh upload my images to a server?
No. Squoosh compresses images locally in your browser, so the image itself never leaves your device. According to the project's GitHub documentation, it collects only basic visit data, image file sizes before and after compression, and installation details through Google Analytics. This makes it suitable for confidential or unreleased images that you would not want to send to an online compression service.
Can Squoosh compress multiple images at once?
No. The Squoosh web app processes one image at a time. Google discontinued its Squoosh command-line tool and Node library, which previously allowed batch compression, and they are no longer maintained. For bulk work, use your CMS's automatic image optimisation, an image CDN, or a maintained library such as Sharp, and keep Squoosh for important images you want to check by eye.
Can Squoosh compress videos or PDFs?
No. Squoosh only works with still images such as JPEG, PNG, WebP, AVIF and GIF files. It cannot compress video files or PDF documents. For video, use a dedicated video encoder or your video host's own processing; for PDFs, use a PDF tool that offers an optimise or reduce file size option.
What is the difference between Squoosh and TinyPNG?
Squoosh compresses images in your browser and gives you detailed control over format and quality, with a side-by-side preview. TinyPNG uploads images to its own servers and compresses them automatically, with very few settings, and it handles several images at once. Choose Squoosh for control and privacy on individual images, and an automatic service when speed across many images matters more.
About the author
Daniel Rowles is lead trainer at Target Internet and the author of Digital Branding (Kogan Page). He co-hosts The Digital Marketing Podcast and delivers digital marketing and AI training for organisations around the world. He covers page speed and technical SEO in Target Internet's SEO and Core Web Vitals training. You can find out more on his Target Internet profile.
Bibliography
1. Google Chrome Labs (2026). Squoosh: README and privacy information. https://github.com/GoogleChromeLabs/squoosh
2. Google for Developers (2026). An image format for the web: WebP. https://developers.google.com/speed/webp
3. web.dev (Google). Using AVIF to compress images on your site. https://web.dev/articles/compress-images-avif
4. Can I Use (2026). AVIF image format: browser support. https://caniuse.com/avif
5. Can I Use (2026). WebP image format: browser support. https://caniuse.com/webp
6. Can I Use (2026). JPEG XL image format: browser support. https://caniuse.com/jpegxl
7. npm (2023). @squoosh/cli: project no longer maintained. https://www.npmjs.com/package/@squoosh/cli
8. web.dev (Google, 2020). Announcing Squoosh v2. https://web.dev/blog/squoosh-v2