Free browser-based image compressor

Free Online Image Compressor

No upload to server Compress and resize JPG PNG WebP AVIF PDF

Tool

Compress, resize, and convert images in one place

Upload a file, choose your settings, preview the result, and download a smaller file without leaving your browser.

1. Upload 2. Adjust 3. Download

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Compare the original and compressed image

Original

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How to use it

Follow these steps to compress, resize, or convert your images and PDFs directly in the browser.

1

Upload your files

Click the upload area or drag and drop your files. You can select up to 100 images or PDFs at once. Supported formats include JPG, PNG, WebP, AVIF, and PDF.

2

Adjust the settings

Choose an output format, set the compression quality with the slider, and optionally resize the dimensions. The aspect ratio lock prevents stretching by default.

3

Preview the result

After processing, the original and optimized files are shown side by side. Check the file size difference, dimensions, and visual quality before downloading.

4

Download your files

Download a single result or get a ZIP archive when processing multiple files. The tool automatically keeps the original if recompression would make the file larger.

Image compression guide

Understanding the settings helps you get the best balance between file size and visual quality.

Choosing the right format

  • JPG works best for photographs and complex images with many colors. It supports lossy compression, which can significantly reduce file size while keeping acceptable quality.
  • PNG is ideal for images with sharp edges, text, screenshots, or transparency. Files are larger but remain lossless, so no detail is removed during compression.
  • WebP provides smaller file sizes than both JPG and PNG in most cases while supporting both lossy and lossless modes. It is widely supported in modern browsers.
  • AVIF offers even better compression than WebP, especially for photographs. Browser support is growing, but it may not work everywhere yet.

Understanding the quality slider

  • 80-100%: Minimal compression. Best for images where every detail matters, such as product photos or professional work.
  • 60-79%: Good balance for web use. Most users will not notice a visible difference, but file sizes drop noticeably.
  • 40-59%: Aggressive compression. Useful when storage or bandwidth is limited. Some artifacts may appear in detailed areas.
  • 10-39%: Maximum compression. Best for thumbnails or preview images where file size matters more than quality.

When to resize

  • Resizing is most effective when your source image is much larger than where it will be displayed.
  • For blog post images, a width of 1200-1600 pixels is usually sufficient.
  • Social media thumbnails often look great at 600-800 pixels wide.
  • Keeping the aspect ratio enabled prevents your image from being stretched or squished.

Tips for best results

Keep these recommendations in mind to get the most out of every compression.

  • Start with the original format and only change it if you have a clear reason. Converting between formats can sometimes introduce artifacts.
  • Process a single file first to test different quality settings, then apply the best setting to the entire batch.
  • Use the side-by-side preview to compare the original and optimized versions before downloading.
  • If the compressed file ends up larger than the original, the tool will automatically keep the original file instead.
  • For screenshots or images with text, use PNG format to keep edges sharp and readable.
  • When compressing photos for email attachments, aim for 50-70% quality to keep attachment sizes manageable.
  • Large batches are processed sequentially. Allow the tool to finish before navigating away from the page.

Common questions

Does this tool upload my image to a server?

No. Image compression and resizing happen entirely in your browser, so your file stays on your device during normal use. No images are sent to or stored on any external server.

Which file formats are supported?

You can upload JPG, PNG, WebP, AVIF, and PDF files. For image outputs, you can export to JPG, PNG, WebP, or AVIF. PDF files can be optimized by removing metadata and recompressing internal streams.

Will compression reduce image quality?

Lower quality settings can reduce detail, which is why the preview and size comparison are shown before download. You can always adjust the quality slider and reprocess if the result does not meet your expectations.

Can I resize without changing the format?

Yes. Select "Keep original format" in the output format dropdown and use the resize options to change dimensions without converting to a different file type.

Is this tool free to use?

Yes. The tool is available in your browser without signup, subscription, or software installation.

How many files can I process at once?

You can upload and process up to 100 files in a single batch. When processing multiple files, the results are packaged into a ZIP file for convenient download.

Why is the compressed file larger than the original?

This can happen when the original file is already highly optimized or uses a lossless format like PNG. The tool detects this and keeps the original file instead, so you never end up with a worse result.

Does it work on mobile devices?

Yes. The tool runs in the browser and works on phones, tablets, and desktop computers. No app installation is needed.

Can I compress PDF files?

Yes. You can upload PDF files and the tool will optimize them by removing unnecessary metadata and recompressing internal content. The preview shows the first page of the PDF.

What happens to my files after processing?

Nothing. All processing happens in your browser's memory. Once you download the results and close the tab, the files are gone. No data is retained on any server.