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100% free · no signupRuns in your browser

Image Compressor

Reduce JPEG file size by re-encoding at chosen quality — 100% in-browser.

Best for: Preparing images for the web, attaching them to email, speeding up a page, or staying under an upload size cap.

Complete guide

Input

How it's calculated & sources
The Image Compressor uses the standard method for this calculation. It runs entirely in your browser, so your inputs are never uploaded. Last reviewed June 2026.

Free & no sign-up · runs entirely in your browser. Results are estimates for general information, not professional advice — verify important decisions with a qualified expert. Last reviewed June 2026.

How it works

Re-encodes the image as JPEG, WebP or PNG at the chosen quality using the canvas toBlob API. 100% runs in your browser — files never leave your device.

Continue your journey

Where people usually head next.

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Color Picker
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Image Resizer
Resize images to any width/height with optional aspect ratio lock.
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Image Converter
Convert images between PNG, JPEG and WebP in your browser.
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Image Cropper
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Complete guide

Quick answers

Short, sourced answers to the questions people (and AI assistants) ask most.

What is Image Compressor?
An image compressor shrinks a photo or graphic's file size so pages load faster and uploads fit within limits. It runs entirely in your browser — your images are never uploaded to a server.
Why does Image Compressor matter?
A smaller file that looks almost identical at normal viewing size. Push the quality too low and you start to see artifacts — blockiness in flat areas and banding in gradients.
How is Image Compressor calculated?
For JPEG and WebP it re-encodes the image at a lower quality setting, discarding fine detail the eye barely registers (lossy). For PNG it strips metadata and optimises the palette and filters without changing a pixel (lossless). You trade a little quality for a much smaller file.
What is a good image compressor?
For photos, JPEG or WebP quality around 75-85 usually gives the best balance of size and clarity. Modern formats (WebP, AVIF) compress noticeably smaller than JPEG at the same visual quality.
What are common image compressor mistakes?
Re-compressing an already-compressed JPEG, which adds generation loss each time.
When should you use the Image Compressor?
Preparing images for the web, attaching them to email, speeding up a page, or staying under an upload size cap.

What is the Image Compressor?

An image compressor shrinks a photo or graphic's file size so pages load faster and uploads fit within limits. It runs entirely in your browser — your images are never uploaded to a server.

How the Image Compressor works

For JPEG and WebP it re-encodes the image at a lower quality setting, discarding fine detail the eye barely registers (lossy). For PNG it strips metadata and optimises the palette and filters without changing a pixel (lossless). You trade a little quality for a much smaller file.

What's a typical value?

For photos, JPEG or WebP quality around 75-85 usually gives the best balance of size and clarity. Modern formats (WebP, AVIF) compress noticeably smaller than JPEG at the same visual quality.

Key terms

Lossy:
Compression that discards some detail permanently for a smaller file (JPEG, WebP).
Lossless:
Compression that reduces size with no quality change (PNG, optimised).
Artifact:
Visible distortion from over-compression, like blockiness or banding.

Common mistakes to avoid

  • Re-compressing an already-compressed JPEG, which adds generation loss each time.
  • Saving photos as PNG — it is lossless and huge for photographs; use JPEG or WebP.
  • Resizing after compressing — shrink the dimensions first, then compress.
  • Pushing quality so low that visible artifacts appear.

Keywords: image, compress, jpeg.

Sources: web.dev — Choose the right image format / optimise

Reviewed by the Free Tools Galaxy editorial team · Updated June 2026 · Calculated privately in your browser.

Frequently asked questions

Is the Image Compressor free to use?+

Yes. Every tool on Free Tools Galaxy is 100% free, runs in your browser and requires no signup.

How accurate is the Image Compressor?+

Image Compressor uses the standard image compressor formula in double-precision arithmetic, so the same inputs always produce the same result and you can verify any figure by hand. It is an educational estimate — real-world outcomes depend on your actual rates, rules and assumptions.

Do you store my inputs?+

No. The Image Compressor runs entirely in your browser. Nothing is uploaded or saved to a server.

Can I use the Image Compressor on mobile?+

Yes — the interface is fully responsive and works on phones, tablets and desktops.

What are common mistakes to avoid?+

The most frequent mistake is mixing units. Double-check your inputs use a single, consistent unit before clicking Calculate.

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Smart Autopilot

AI-style routing · 100% on-device

Based on this tool, your recent activity and how others chain tools together.

Likely next step

🎨Color PickerTop match📐Image ResizerResize images to any width/height with optional aspect ratio lock.🔄Image ConverterConvert images between PNG, JPEG and WebP in your browser.✂️Image CropperCrop any image to a custom rectangle entirely in your browser.🔃Image RotatorRotate any image by any angle and download losslessly.🔁Image FlipperFlip an image horizontally or vertically in one click.

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Share & publish

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Share-to-grow kit (Reddit, LinkedIn, Medium)
Reddit post
Title: I built/used this free image compressor — instant, no signup

Body: Reduce JPEG file size by re-encoding at chosen quality — 100% in-browser. Try it: https://freetoolsgalaxy.com/tools/image-compressor
LinkedIn post
Image Compressor on Free Tools Galaxy — Reduce JPEG file size by re-encoding at chosen quality — 100% in-browser. https://freetoolsgalaxy.com/tools/image-compressor
Medium intro
# Image Compressor — the free tool I keep coming back to

Reduce JPEG file size by re-encoding at chosen quality — 100% in-browser.

Try it: https://freetoolsgalaxy.com/tools/image-compressor
Quora answer
The fastest way is to use a free in-browser image compressor: https://freetoolsgalaxy.com/tools/image-compressor. Reduce JPEG file size by re-encoding at chosen quality — 100% in-browser.

Embed this tool anywhere

Free embed code for blogs, docs and dashboards. Every embed sends a backlink home — helping you and the galaxy grow together.

HTML iframe
Drop into any site — auto-resizes to its content height, theme-aware.
<iframe src="https://freetoolsgalaxy.com/tools/image-compressor?embed=1" title="Image Compressor" loading="lazy"
  style="width:100%;height:600px;border:0;border-radius:16px;background:#0b1020"
  allow="clipboard-write"></iframe>
<script>window.addEventListener("message",function(e){if(e.data&&e.data.type==="ftg-embed-height"){document.querySelectorAll("iframe").forEach(function(f){if(f.contentWindow===e.source){f.style.height=e.data.height+"px";}});}});</script>
<p><a href="https://freetoolsgalaxy.com/tools/image-compressor" target="_blank" rel="noopener">Powered by Image Compressor on Free Tools Galaxy</a></p>
Responsive wrapper
Aspect-locked container — good for blog post bodies.
<div style="position:relative;padding-bottom:75%;height:0;overflow:hidden;border-radius:16px">
  <iframe src="https://freetoolsgalaxy.com/tools/image-compressor?embed=1" title="Image Compressor" loading="lazy"
    style="position:absolute;inset:0;width:100%;height:100%;border:0" allow="clipboard-write"></iframe>
</div>
WordPress / Markdown
Paste in a custom-HTML block or markdown file.
[Image Compressor — free online tool](https://freetoolsgalaxy.com/tools/image-compressor)

<iframe src="https://freetoolsgalaxy.com/tools/image-compressor?embed=1" width="100%" height="600" frameborder="0"></iframe>
Text link-back
Minimal credit link — best for sidebars and footers.
<a href="https://freetoolsgalaxy.com/tools/image-compressor" target="_blank" rel="noopener">Try the free Image Compressor</a>

Share-to-Grow Kit

Pre-written, ready-to-paste posts for every major channel. Help others discover this tool — and earn backlinks.

Title
I built a free fraction calculator that works instantly in the browser — no signup, no ads in your face
Body
Hey r/[subreddit],

I kept needing a quick fraction calculator and most options online were slow or behind paywalls, so I built one that:

• Runs 100% in your browser (your data never leaves your device)
• No signup, no email wall, no popups
• Loads in under a second on mobile

It covers the standard fraction use cases (fraction, math) and links out to the formula + worked examples if you want to learn the math.

Link: https://freetoolsgalaxy.com/tools/fraction-calculator

Happy to take feedback — what's missing?
Post to a relevant subreddit (e.g. r/InternetIsBeautiful, r/webdev, r/productivity). Avoid spammy subs.
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