Image Compressor
Drop your images and get smaller files in seconds. Choose a quality, resize or convert to WebP, compare before and after with a slider, and download one image or a ZIP. Everything happens in your browser, so your images are never uploaded.
- Private: no upload
- JPG, PNG, WebP and SVG
- Before and after slider
Check how heavy the images on a page are with the Image SEO Checker, or measure the speed effect with the Website Performance Checker.
Smaller images, same look
Lighter images load faster, which helps visitors, Core Web Vitals and your hosting bill.
Private by design
Your images are processed on your own device. Nothing is uploaded, so confidential photos and client files stay with you.
Real PNG compression
PNGs are reduced to an optimised palette, which commonly cuts them by half or more. Pictures with 256 colours or fewer are kept exactly the same.
You choose the balance
Pick a preset, drag the quality slider, or set a maximum file size and let the tool find the best quality that fits.
Resize and convert
Limit the width, and convert to WebP for the smallest files or to JPEG for photos.
See the difference
A before and after slider shows exactly what changed, so you can lower the quality until it just starts to show.
Never bigger
If an image cannot be made smaller, the original is kept as it is, so you never download a larger file.
Which format for which image?
The right format often saves more than the quality setting does.
| Image | Best format | Why |
|---|---|---|
| Photographs | WebP or JPEG | Both are built for continuous tones. WebP is usually 25 to 35% smaller at the same look. |
| Logos, icons and flat graphics | SVG, or PNG | SVG stays sharp at any size. A palette PNG is small for flat colours and sharp edges. |
| Screenshots | PNG or WebP | Text edges stay crisp in PNG. WebP is smaller when you can accept it. |
| Images with transparency | PNG or WebP | JPEG cannot be transparent. WebP supports transparency in a much smaller file. |
| Animations | Keep as is | This tool skips animated GIF, PNG and WebP files so they do not lose their animation. |
How to compress images
Three steps, and no sign-up.
Add your images
Drop up to 40 images on the box, choose files, or paste one from your clipboard.
Pick a quality
Start with Balanced. Use the slider, a maximum width or a target file size to go smaller.
Check and download
Use the compare slider if you like, then download each image or everything as a ZIP.
Tips for the best results
A few habits that keep images light without hurting quality.
Resize before you compress
A 4000 px photo shown at 800 px wastes bytes. Set a maximum width close to the size it is displayed at.
Convert photos to WebP
WebP is supported by every modern browser and is usually the smallest choice for photos and for images with transparency.
Look before you commit
Open the compare slider and zoom into edges, gradients and faces. If you cannot see a difference, go lower.
Keep your originals
Compression is lossy for JPEG, WebP and reduced-colour PNG. Keep the originals and publish the compressed copies.
Use descriptive names
Name files with what they show, such as red-running-shoes.webp. Good file names and alt text help image search.
Test the page
After you replace the images, run the Website Performance Checker or the Core Web Vitals Checker to see the effect.
What image compression is and how to compress images for the web
Image compression makes a picture file smaller. There are two kinds. Lossless compression keeps every pixel exactly as it was, and lossy compression throws away detail the eye is unlikely to miss. The MDN guide to image formats suggests lossless for screenshots, logos and line art, where blur around text and edges shows, and lossy for photographs.
It matters because images are often the heaviest part of a page. A page that loads a large photo as its main picture takes longer to show it, and the time to draw the largest visible element is what Largest Contentful Paint measures. Google's guideline for a good result is 2.5 seconds or less. Lighter images also save mobile data for your visitors and bandwidth on your hosting.
File size comes down to four things: the dimensions, the format, the quality setting and the metadata kept in the file. This tool lets you control the first three in your browser and drops the metadata when it re-encodes. Your images are never uploaded, so it is safe for private or client files. Use the compare slider to lower the quality until a difference just starts to show, then stop. If the page needs more than compression, the Image SEO Checker shows which images to tackle first.
When to compress your images
Compress at the end of your editing, just before the image goes into a page, post or product listing.
Before uploading to your CMS
Phone and camera photos can be several megabytes. Resize and compress them first, so every post, product or page you publish starts light instead of relying on a plugin to fix it later.
For product and catalogue photos
A category page can show dozens of thumbnails at once. Compressing a whole folder in one go, then downloading a ZIP, keeps a store fast without editing each file by hand.
After a speed test flags images
If a speed report mentions oversized or poorly encoded images, compress the files it names and run the test again to see whether the page got faster.
For confidential or client files
Because the work happens on your device, you can shrink unreleased designs, ID scans or client photos without sending them to a third-party server.
To fit an upload or email limit
Set a target size in KB and the tool looks for the best quality that fits. It is handy for forms, job portals and email attachments with a file size cap.
When switching to WebP
Convert JPEG and PNG files to WebP in bulk and compare the result with the original. Keep the old files until you have checked how each image looks in place.
Image compression mistakes and how to fix them
Most wasted bytes come from sending the wrong size or format, not from the quality slider.
Compressing without resizing
What goes wrong: A 4000 pixel photo shown in an 800 pixel space still carries pixels nobody sees. Lowering quality alone leaves most of the weight in place.
The fix: Set a maximum width close to the largest size the image is displayed at, then compress. Lighthouse's Properly size images audit shows which files are too big.
Re-compressing already compressed files
What goes wrong: Each lossy save discards more detail. Compressing a JPEG that was itself exported from a compressed copy can add visible blocks and smearing.
The fix: Always start from the original or the highest quality version you have. Keep the originals in a separate folder and publish only the compressed copies.
Using JPEG for logos and screenshots
What goes wrong: Lossy JPEG blurs hard edges and leaves coloured fringes around text, and it cannot store transparency.
The fix: Choose SVG for logos and icons where you can, or PNG or WebP for screenshots and graphics. Zoom in on edges with the compare slider before you accept the result.
Saving photographs as PNG
What goes wrong: PNG is lossless, so a photo saved as PNG is often much larger than the same picture as JPEG or WebP, with no visible benefit.
The fix: Use JPEG or WebP for photographs, and keep PNG for images that really need lossless detail or transparency, such as a small graphic.
Compressing animated GIFs
What goes wrong: Re-encoding in the browser can flatten an animation to one frame, so this tool skips animated files. Large animated GIFs are also heavy on their own.
The fix: Leave the GIF as it is, or replace it with a short video file, which is usually far smaller. web.dev has a guide for converting GIFs to video.
Forgetting what compression removes
What goes wrong: Re-encoding drops metadata such as camera details and location, and colour profiles are not kept, so unusual colour spaces can shift slightly.
The fix: Keep the original files for anything that needs its metadata or exact colours, such as photography portfolios, and check colour-critical images side by side.
Image compression terms explained
- Lossy compression
- A method that discards some image data to get a much smaller file. JPEG is lossy in everyday web use, and WebP and AVIF can. The quality slider controls how much is discarded.
- Lossless compression
- A method that makes a file smaller without changing a single pixel. PNG is lossless, which suits screenshots, diagrams and line art but gives larger files for photographs.
- Quality setting
- A number from 0 to 100 for lossy formats. Lower values give smaller files and more visible loss. This tool offers presets of 60, 80 and 92 and a free slider.
- WebP
- An image format that handles photographs and transparency. A Google study of WebP reported lossy files 25 to 34 percent smaller than JPEG at the same SSIM quality score.
- Reduced-colour PNG
- A PNG rewritten to use a smaller list of colours. It can cut flat graphics by a large amount, but gradients and photographs may show banding, so check them before you publish.
- EXIF metadata
- Information stored inside a photo about how it was taken, such as pixel size, exposure settings and capture date. Re-encoding the image through this tool removes it.
- Alpha transparency
- The channel that lets parts of an image be see-through. JPEG has no alpha channel, while PNG and WebP can keep transparency.
- Target file size
- A size limit in KB. The tool searches for the highest quality that fits under it, and tells you if no setting can reach the target.
Related tools, guides and services
Compressing is one step. These help you find the right images and measure the result.
Image SEO Checker
Scan a page to find the heaviest images, missing alt text and formats worth changing.
ToolWebsite Performance Checker
Run a speed test before and after replacing images to see what changed.
ToolCore Web Vitals Checker
Check whether lighter images improved your Largest Contentful Paint.
GuideSEO for Nepali ecommerce
Read how product images and page speed fit into an online store's SEO.
ServiceTechnical SEO service
Get image delivery, caching and page speed reviewed across your whole site.
Built by
Madhav Kushwaha
Most online compressors upload your images to a server and give you no say in how they are squeezed. I built this one to run entirely in your browser, to compress PNGs properly instead of just re-saving them, and to show you the result before you download. I use it to prepare the images for this website.
Image Compressor: Frequently Asked Questions
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