Free Image Compressor
Make JPG, PNG and WebP images smaller before they slow your site down. Resize them, convert them to WebP and download the lighter files. Everything happens in your browser: your images are never uploaded.
At a glance
- Resize first, then compress. Most oversized images are simply too many pixels for where they're shown.
- WebP at quality 75–85 is the best starting point for photos on websites.
- Nothing is uploaded: the compressor uses your browser's own image tools, so it's private and fast.
- Compressed images also drop hidden photo data, including camera details and GPS location.
Why image size matters
Images are the heaviest thing most pages load. The HTTP Archive's 2024 Web Almanac measured the median mobile page at 2,311 KB, and the median mobile homepage loads about 900 KB of images, more than any other kind of file. The biggest image near the top is also often the page's Largest Contentful Paint, one of Google's Core Web Vitals, which should happen within 2.5 seconds. A 4 MB phone photo used as a 1200px-wide banner forces every visitor to download far more than they see, which hurts most on mobile data. Our guide to Core Web Vitals explains how that feeds into page experience, and image SEO covers the rest of getting images found.
How to compress images for your website
- Choose WebP unless the place you're uploading to doesn't accept it.
- Set a maximum width: 1600 px for images inside an article, 2000 px for full-width banners, smaller for thumbnails.
- Start at quality 80 and drop the images in.
- Check the result: open a compressed file next to the original. If you can see blur or blocky edges, raise the quality.
- Download and replace the originals on your site, keeping the same file names if your pages already link to them, or update the links.
- Measure the page again with the Image Size Checker.
WebP vs JPEG vs PNG vs AVIF: which format to choose
Use WebP for almost everything on a website. Google's WebP documentation reports lossy WebP files 25–34% smaller than comparable JPEGs at the same measured quality, and lossless WebP 26% smaller than PNG. Browser support is no longer a worry: Can I use puts WebP support at about 97% of browsers in use, including Safari since version 16 on Mac and 14 on iPhone. WordPress has accepted WebP uploads since version 5.8.
| Format | Best for | Notes | This compressor saves it? |
|---|---|---|---|
| WebP | Photos, screenshots, illustrations | Lossy or lossless, with transparency. Supported by about 97% of browsers in use | Yes (recommended) |
| JPEG | Photos where WebP isn't accepted | Universal; larger than WebP at the same visual quality | Yes |
| PNG | Logos and graphics needing exact pixels or transparency | Lossless, so often large for photos | Yes (keeps PNG) |
| AVIF | Photos, when you can generate it | Often smaller than WebP; about 96% browser support, but slow to encode | No: browsers can't save AVIF yet |
| SVG | Logos and icons drawn as shapes | Not a photo format | No |
AVIF can be smaller still, and about 96% of browsers display it, but browsers can't save it from a web page yet, so making AVIF needs an image editor, a build tool or an image CDN. WebP is the practical choice for a quick, private compression.
Real results: two of our own blog images
Two illustrations on one of our older blog posts were still the original PNG files. We ran them through this compressor at the default settings (WebP, quality 80):
| Image (1024 × 559 px) | Original PNG | WebP, quality 80 | JPEG, quality 80 |
|---|---|---|---|
| Content strategy illustration | 897 KB | 88 KB (90% smaller) | 112 KB (88% smaller) |
| Search on a smartphone illustration | 641 KB | 36 KB (94% smaller) | 56 KB (91% smaller) |
Side by side at the size they're shown, the WebP versions look the same. That's typical for PNGs used for photos and illustrations: PNG keeps every pixel exactly, which is wasted on images like these. Photos that are already JPEGs vary more: one saved at high quality still has a lot to give (our phone photo below went from 507 KB to 41 KB), while one that's been compressed before shrinks less, and resizing it to the width it's actually shown at saves the most.
How to compress an image to 100 KB (or any size)
Resize first, then lower the quality in steps of 5 until the file is under your target. Width does more than quality: halving the width cuts the pixel count to a quarter. We ran two real images through this compressor at every setting, so you can see what each one does:
| Setting | 1024 × 559 PNG illustration (897 KB) | 720 × 1280 phone photo, JPEG (507 KB) |
|---|---|---|
| WebP, quality 90 | 135 KB | 65 KB |
| WebP, quality 80 (default) | 88 KB | 41 KB |
| WebP, quality 70 | 69 KB | 32 KB |
| WebP, quality 60 | 61 KB | 29 KB |
| WebP 80, resized to 800 px wide | 53 KB | Already narrower than 800 px |
| JPEG, quality 80 | 112 KB | 79 KB |
| JPEG 80, resized to 800 px wide | 69 KB | Already narrower than 800 px |
Three things stand out. WebP at the default setting was 21% smaller than JPEG for the illustration and 48% smaller for the photo, in line with Google's figures (quality numbers aren't exactly equal across formats, so treat that as a rough comparison). Resizing the illustration from 1024 to 800 pixels saved another 40%. And going from quality 80 to 60 saved much less than resizing did, while starting to blur fine edges.
- Set the width to the size the image is actually shown at (doubled for sharp screens, if your target allows).
- Choose WebP unless the upload form demands JPEG.
- Start at quality 80. Over target? Drop to 75, then 70.
- Still too big? Reduce the width again rather than going below quality 60. For tight limits such as 50 KB or 20 KB on job or visa forms, a width of 600 px or less is usually needed.
- Check it at full size before you upload: faces and text show compression first.
Is it safe to use an online image compressor?
It's safe when the images never leave your device, as here. Many online compressors upload your files to their servers. This one decodes and re-saves each image inside your browser using the canvas toBlob() feature, so nothing is sent anywhere. You can check this yourself: open your browser's developer tools (F12), go to the Network tab, then drop in an image. No upload request appears. Re-saving through the browser also drops hidden metadata such as GPS location, which matters for photos taken at home.
Lossy and lossless compression, in plain words
Lossless compression (PNG, and WebP in lossless mode) packs the image more tightly without changing a single pixel, like zipping a file. It's ideal for logos, icons and screenshots of text, where sharp edges matter, but saves little on photos. Lossy compression (JPEG, and WebP at a quality setting) throws away detail your eye is unlikely to notice, such as tiny colour variations in a sky. The quality slider controls how much: at 80 the loss is very hard to see; below about 60 you may notice blur and blocky edges.
Image sizes to aim for
| Where the image goes | Width to save at | A sensible target |
|---|---|---|
| Full-width banner or hero | 1920–2000 px | Under about 300 KB |
| Image inside an article | 1200–1600 px | Under about 150 KB |
| Product photo | 1200–1600 px, square or 4:5 | Under about 200 KB |
| Thumbnail or card | 400–600 px | Under about 50 KB |
| Social share image (og:image) | 1200 × 630 px | Under 1 MB; 5 MB is the hard limit on some platforms |
These are starting points, not rules: an image packed with fine detail will be bigger than a flat illustration at the same width. If your site serves the same image to phones and large screens, ask your developer about responsive images (the srcset attribute), which lets each device download a size that fits it. The Image Size Checker shows the actual weight and dimensions of every image on a live page, and Google's image SEO best practices cover alt text and file names.
Common image mistakes on websites
- Uploading straight from the camera: 12-megapixel photos for a 600px slot.
- PNG for photos, which can be several times larger than WebP or JPEG.
- Compressing the same JPEG again and again, which adds blur each time. Start from the original.
- Forgetting width and height on the <img> tag, so the page jumps as images load (layout shift).
- Lazy-loading the main image at the top of the page, which delays it. Lazy loading is for images further down the page.
What the image compressor doesn't do
- It doesn't change SVG or GIF files. SVGs are already small shapes; animated GIFs are better replaced with video.
- It doesn't keep metadata. Copyright fields are removed along with camera and location data.
- It can't make AVIF in most browsers yet; WebP is the safe choice today.
- It doesn't touch your website. Upload the new files yourself, or ask your developer to add automatic image optimization.
Image compression on one map
Your next step
Run your homepage through the Image Size Checker, take the three heaviest images it lists, compress them here as WebP at quality 80 and the width they're shown at, and replace the originals. Then re-test the page: the images near the top are usually what's holding back your Largest Contentful Paint.
Find heavy images across your whole site
Watch Owl crawls up to 500 of your pages in a real browser and reports images that fail to load or are missing size attributes.
Frequently asked questions
How do I compress an image without losing quality?
Resize it to the largest width it's actually shown at, then save it as WebP at a quality around 75–85. At that setting most photos look the same to the eye and are a fraction of the size. Compare the before and after side by side before you replace the original.
Are my images uploaded to your servers?
No. The compressor runs in your browser using its built-in image tools. Your images never leave your device, and nothing is stored.
Should I use WebP or JPEG?
WebP for websites: every current browser supports it and it's usually much smaller than JPEG at the same quality. Use JPEG when a platform or email tool doesn't accept WebP.
Why did my PNG get bigger?
PNG is lossless, so re-saving a PNG as PNG can't throw detail away and may grow. Convert photos and screenshots to WebP instead; keep PNG only for images that need exact pixels.
What size should website images be?
As wide as they're displayed, and about twice that for sharp screens: a 800px-wide content image can be saved at around 1600px. Full-width hero images rarely need more than 2000px.
Does compression remove photo location data?
Yes. Saving through the browser drops hidden metadata such as camera details and GPS location, which is good for privacy. If you need to keep copyright information in the file, add it again in your image editor.
Can I compress images for Instagram or WhatsApp?
Yes, but those apps compress again when you upload. Keep a high quality (85 or more) so their compression doesn't stack on yours.
How many images can I compress at once?
Up to 20 per batch. Very large photos may take a few seconds each on older phones.
Is WebP better than PNG?
For photos and illustrations, yes: Google reports lossless WebP 26% smaller than PNG, and lossy WebP is far smaller again. Keep PNG for images that need exact pixels, such as some logos or screenshots of small text.
How do I compress an image to 100 KB?
Resize it to the width it's shown at, choose WebP and start at quality 80, then lower the quality in steps of 5 until it's under 100 KB. If it's still too big at quality 60, reduce the width instead of the quality.
Sources
- Web Almanac 2024: Page Weight, HTTP Archive, 2024
- Largest Contentful Paint (LCP), web.dev, 2026
- An image format for the web (WebP), Google for Developers, 2026
- WebP image format: browser support, Can I use, 2026
- AVIF image format: browser support, Can I use, 2026
- WordPress 5.8 adds WebP support, Make WordPress Core, 2021
- HTMLCanvasElement: toBlob() method, MDN Web Docs, 2026
- Serve responsive images, web.dev, 2026
- Optimize Cumulative Layout Shift, web.dev, 2026
- Browser-level image lazy loading for the web, web.dev, 2026
- Google image SEO best practices, Google Search Central, 2026
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