Image Compressor – Reduce Image File Size Free Online

Compress JPEG, PNG, and WebP images instantly in your browser. No upload, no sign-up. Shrink photos by up to 90% — free online image compressor.

Shrink any image in seconds, right in your browser

Drop in a photo, slide the quality dial, and download a smaller file — no upload, no account, no waiting. The image compressor runs entirely in your browser, so your images never leave your device.

Smaller images load faster in browsers, pass upload-size limits on apps and forms, and cost less to store. A 4 MB camera photo can often drop to under 300 KB with no visible quality difference.

How to compress an image (3 steps)

  1. Drop or choose your image. Click the upload area or drag a JPEG, PNG, or WebP file onto it. Files up to 20 MB are supported.
  2. Set the quality. The slider goes from 10 (smallest file, most compression) to 100 (largest file, least compression). For photos, 75–85 is a sweet spot that keeps them looking sharp.
  3. Download. Hit Download Compressed Image. You get the compressed file instantly, in the same format as your original.

The size-before and size-after figures are shown right on screen so you can see exactly how much space you saved before you commit to downloading.

Worked example: compressing a product photo

Input: a JPEG product photo straight from a camera — 3.8 MB, 4000 × 3000 px.

Quality set to: 80

Output: 310 KB — roughly a 92% reduction — with colours and detail that look identical on screen at normal viewing sizes.

If you need to hit a specific upload limit (say, 200 KB for a profile picture), slide the quality down gradually and watch the file size update. Most photos reach 200 KB somewhere between quality 60 and 75.

How to do this in code (Python & JavaScript)

If you need to compress images programmatically — for example, in a build pipeline or a server-side upload handler — here are the standard one-liners.

Python (Pillow)

# pip install Pillow
from PIL import Image

img = Image.open('photo.jpg')
img.save('photo_compressed.jpg', quality=80, optimize=True)

The quality parameter maps directly to JPEG quality (1–95). optimize=True runs an extra pass to squeeze out a few more bytes. See the Pillow JPEG docs for all options.

JavaScript (browser Canvas API)

// Draw image to canvas, then export at reduced quality
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
canvas.width = img.naturalWidth;
canvas.height = img.naturalHeight;
ctx.drawImage(img, 0, 0);

// Second argument is quality: 0.0 (smallest) to 1.0 (best)
convas.toBlob(blob => {
  const url = URL.createObjectURL(blob);
  // use url to trigger download or display
}, 'image/jpeg', 0.80);

This is exactly what the tool above does under the hood — the browser's built-in canvas.toBlob() handles the JPEG encoding. Check MDN: canvas.toBlob() for the full API reference.

How it works

When you load an image, the tool draws it onto an off-screen HTML5 Canvas element. The Canvas API's toBlob() method then re-encodes the pixel data as JPEG (or WebP) at the quality level you chose.

Lower quality means the JPEG encoder discards more high-frequency detail — fine textures and subtle gradients — that the eye barely notices at normal zoom. The file gets smaller because there is simply less data to store.

Everything happens locally. No image data is sent to any server. The compression runs on your CPU, inside your browser tab.

When to use this tool — and when not to

SituationGood fit?Notes
Reducing a photo for a web page or blog post✅ YesJPEG quality 75–85 is standard for the web
Passing a file-size limit on a form or app✅ YesSlide quality down until the displayed size is under the limit
Sending a photo by email or messaging app✅ YesCuts load time and data usage for the recipient
Compressing a logo or icon with transparency⚠️ PartialPNG compression is lossless here — quality slider has no effect on PNGs; use a dedicated PNG optimiser for those
Archiving original files you may need to edit later❌ NoKeep the uncompressed original; JPEG compression is lossy and cannot be reversed
Print-quality output (magazines, large-format prints)❌ NoStay at quality 95+ or use a lossless format like TIFF

Your images stay private

The tool runs 100% client-side. Your image is loaded into browser memory, compressed on your device using the Canvas API, and the result is handed straight back to you. Nothing is uploaded to any server, logged, or stored anywhere outside your browser tab.

Need to work with structured data formats too? Check out our JSON Beautifier to format messy JSON, or use the JSON Minifier to strip whitespace and shrink JSON payloads before sending them over the wire.

Takeaway: compressing images before you publish or upload them is one of the fastest wins in web performance — drop your image into the tool above and see the difference in seconds.

Frequently asked questions

Is my image uploaded to a server when I compress it?+
No. The entire compression process runs in your browser using the HTML5 Canvas API. Your image never leaves your device and is never sent to any server. It's safe to use with sensitive or private photos.
Is this tool free? Do I need to sign up?+
Completely free, no account required. Open the page, drop your image, download the result — that's it.
What image formats does it support?+
JPEG, PNG, and WebP. JPEG and WebP benefit most from the quality slider (lossy compression). PNG is re-exported losslessly, so the size reduction for PNGs is modest; a dedicated PNG crusher like PNGQuant gives better results for transparent graphics.
What quality setting should I use?+
For photos on a website, 75–85 is the standard sweet spot — files are 60–90% smaller than the original with no visible loss at normal screen sizes. For profile pictures or thumbnails, 65–75 works well. Drop below 60 only if you really need the smallest possible file and can accept some softness.
How do I compress an image to under 100 KB (or 200 KB)?+
Upload the image, then watch the 'Compressed size' figure while you drag the quality slider down. Stop when it shows the number you need. Most photos reach 100 KB somewhere between quality 50 and 70, depending on their original size and content.
Does compressing an image reduce its dimensions (width and height)?+
No. This tool only changes the file size by adjusting encoding quality — the pixel dimensions stay exactly the same. If you also need to resize the image to smaller dimensions, you'll need a separate image resizer.
Can I compress large files — like a 15 MB RAW or high-res photo?+
Files up to 20 MB are supported. Very large files may take a second or two to process, depending on your device, but there's no server timeout to worry about since everything runs locally.
What's the difference between lossy and lossless compression?+
Lossy compression (used here for JPEG and WebP) permanently removes some image data to make the file smaller — the lower the quality setting, the more data is removed. Lossless compression (used for PNG) reorganises the data so it takes up less space, but nothing is discarded and the image looks pixel-perfect. Lossy almost always achieves far smaller file sizes for photographs.