About CompJPG

Free · Private · No Uploads · Built for Everyone

What is CompJPG?

CompJPG is a free, browser-based JPEG compressor and JPG-to-WebP converter that helps you reduce image file size while checking the effect on visual quality. Whether you're a photographer preparing images for the web, a blogger optimizing page load times, or just someone who needs to email a photo that's too large — CompJPG is built for you.

Who builds CompJPG

Pradeep Maskeri — creator, developer and author of the guides on this site

I'm an engineer with four decades of experience in image processing, alongside work in electronics design and hardware/software integration. CompJPG started as a tool I wanted for myself: a way to get a photo under a strict upload limit without sending it to someone else's server. I built it in C# with Blazor WebAssembly and MozJPEG, and I write and test every guide here against the tool itself.

Found a mistake in a guide or a file the tool handles badly? Email me at support@compjpg.com — corrections are welcome.

Why I Built This

Many compression services process files on a remote server. I wanted an option where the image processing stays on your own device, with no account or upload step.

Modern browsers made that practical: they can decode and re-encode images locally using the HTML5 Canvas API and WebAssembly libraries such as MozJPEG. CompJPG is built around that:

  • Zero uploads — your images never leave your device
  • No server processing — everything runs in your browser
  • No account required — just drop your files and compress
  • Clear limits — JPG, PNG and WebP input, up to 30 MB per file
  • Batch processing — compress up to 20 images at once

How It Works

CompJPG uses two compression approaches depending on your needs:

🎚️ Quality Mode

Select a quality level from 10 to 100, then choose Compress JPG or Convert to WebP. JPG output uses MozJPEG when available, with a browser fallback; WebP uses the browser's encoder. Pixel dimensions stay unchanged by default; resizing is optional. Inspect the result with the comparison slider and zoom controls, and use Undo to try another setting.

📦 File Size Mode

Enter a maximum size in KB. The tool tries quality settings and keeps a result within the limit when possible. If the image cannot fit at its current dimensions, it shows a warning instead of claiming success. Encoding speed depends on the image and your device.

Our Technology

CompJPG is built with modern, open-source technologies:

  • Blazor WebAssembly — Microsoft's framework for building interactive web applications with C# and .NET
  • HTML5 Canvas API — the browser's native image processing capability
  • MozJPEG (via WebAssembly) — a trusted open-source library for smart, target-based compression
  • JSZip — for packaging multiple compressed images into a downloadable ZIP file

Who Is This For?

📸

Photographers

Prepare high-resolution shots for web galleries, client proofs, or social media sharing without losing important detail.

✍️

Bloggers & Content Creators

Optimize every image on your blog for faster page loads and better Core Web Vitals — your SEO will thank you.

🛒

E-Commerce Sellers

Compress product photos to meet marketplace file size requirements without making them look low-quality.

💼

Professionals & Teams

Quickly compress documents, screenshots, or images before emailing or uploading to company portals — all without exposing files to third parties.

Our Commitment

  • ✅ Always free — no hidden charges, no premium tiers for basic features
  • ✅ Always private — your files stay on your device, period
  • ✅ No ads on the compressor itself — ads are placed around the tool, never interrupting your workflow
  • ✅ Continuously improved — we're always adding new features and formats

What the tool does not do

CompJPG does not crop images or restore detail already lost in a JPEG. It can reduce pixel dimensions when you set a maximum width/height, but it keeps them unchanged by default. PNG and WebP files are accepted as input, but output is always JPG or WebP, and transparent areas become white. Both outputs can be lossy, so keep your original when you need a master copy for editing or printing.

The image-processing steps run locally. The website can still make network requests to load the app, fonts, or advertising; see the privacy policy for that distinction.

For corrections, support, or feedback, email support@compjpg.com.

Get Started

Ready to compress your images? Head to the CompJPG compressor and drop your files — it takes seconds.

Have questions? Check out our blog for guides on image compression, or contact us directly.