HTML Online Image Optimizer
Compress and resize your images right in your browser to shrink file size, speed up page loads and improve your SEO. The HTMLimg Image Optimizer supports JPG, PNG, WebP and GIF, works entirely on your device, and never uploads a single byte to a server.
or
MaxW:
MaxH:
Width:
Height:
MinW:
MinH:
png to jpeg threshold:
Relax mode:
Fix jpg orientation:
Compression ratio:
{{outputImgWidth}} × {{outputImgHeight}}px {{outputSize}}
Improvement: {{compressRatio}}
Why optimize your images?
Images are usually the heaviest part of a web page. Unoptimized photos can be several megabytes each, forcing visitors, especially on mobile, to wait while they download. Optimizing images compresses that data without a noticeable drop in quality, which directly improves the metrics that matter:
Faster load times
Smaller files download quicker, improving Largest Contentful Paint (LCP) and overall page speed for every visitor.
Better SEO rankings
Google uses Core Web Vitals as a ranking signal. Lighter pages score higher and are crawled more efficiently.
Lower bandwidth costs
Serving fewer bytes reduces hosting and CDN bills, and saves your visitors' mobile data allowances.
Higher conversions
Studies repeatedly show that faster pages keep users engaged and reduce bounce rates, lifting conversions.
How to use the image optimizer
- Add your image. Drag & drop a file onto the box above, or click Browse File to pick one from your device.
- Choose an output format. Keep the same format, or convert to WebP, JPEG, PNG or GIF using the Extension dropdown.
- Set the dimensions (optional). Enter a MaxW/MaxH to cap the size, or a fixed Width/Height to resize precisely.
- Adjust compression. Fine-tune the compression ratio and advanced options, then press Update to re-process.
- Download. Compare the before/after sizes and the improvement percentage, then click Download to save the optimized image.
Optimizer settings explained
The optimizer exposes the same controls a professional build pipeline would. Here is what each one does:
| Setting | What it does |
|---|---|
Extension | Output format. Choose same to keep the original type, or convert to png, jpeg, webp or gif. WebP usually produces the smallest files. |
MaxW / MaxH | Maximum width and height in pixels. The image is scaled down to fit within these bounds while keeping its aspect ratio. Great for capping oversized photos. |
Width / Height | Force an exact output size in pixels. Leave at 0 to keep the natural dimensions. |
Compression ratio | Quality from 0.05 (smallest) to 1 (best quality). 0.6-0.8 is the sweet spot for most web photos. |
PNG to JPEG threshold | If a PNG is larger than this size it is automatically converted to JPEG, which compresses photographic content far better. |
Relax mode | When on, the tool keeps the result only if it is actually smaller than the original, avoiding accidental size increases. |
Fix jpg orientation | Reads the EXIF orientation flag and rotates the image so it always displays the right way up. |
Which format should you choose?
WebP
Modern, supported by all current browsers. Best overall, 25-35% smaller than JPEG at the same quality. Use it as your default for photos and graphics.
JPEG
Ideal for photographs and complex, colourful images. Universally supported. Use when you need maximum compatibility.
PNG
Lossless with transparency. Best for logos, icons, screenshots and flat graphics, but avoid it for photos, where files balloon.
GIF
Limited to 256 colours but supports simple animation. Reserve it for short animated clips; modern alternatives are usually better.
Best practices for image optimization
- Resize before you compress. Never serve a 4000px photo in a 600px slot. Scale it down first using MaxW/MaxH.
- Prefer WebP. Convert JPG and PNG assets to WebP for the biggest savings with no visible quality loss.
- Match quality to content. Hero photos can tolerate stronger compression than text-heavy screenshots.
- Combine with responsive images. Pair optimized files with
srcsetand the<picture>tag to serve the right size per device. - Add lazy loading. Use
loading="lazy"so off-screen images don't block the initial render.
Frequently asked questions
Is this image optimizer free? Are my images uploaded anywhere?
Yes, it is completely free with no limits. All compression and resizing happens locally in your browser using JavaScript, so your images are never uploaded to any server. The tool even works offline once the page has loaded, which makes it both fast and fully private.
Which image formats can I optimize?
You can optimize JPG/JPEG, PNG, WebP and GIF images. You can also convert between formats, for example turning a heavy PNG screenshot into a WebP or JPEG to dramatically cut its file size.
How much smaller will my images get?
It depends on the original format and content, but lossy compression of photos typically reduces file size by 40-80% with little to no visible quality loss. Converting PNG photos to WebP or JPEG can save even more. The tool shows you the exact before/after sizes and the improvement percentage.
What compression ratio should I use?
A compression ratio between 0.6 and 0.8 is a good balance of quality and size for most web images. Drop it lower for thumbnails and background images where detail matters less; raise it for important hero imagery.
Will optimizing affect image quality?
Lossy formats (JPEG, WebP, GIF) discard some data to save space, but at sensible quality settings the difference is invisible to the eye. PNG compression is lossless. Always preview the result before downloading.
Further reading: Wikipedia on image compression, Google's web.dev performance guides, and the MDN image format guide.
Ready to make your website faster? Drop an image above and download the optimized version in seconds.
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