Compress JPG Images Online for Free
Reduce JPEG file sizes with the quality slider and instant file size preview. Compare before and after, then download. All processing happens in your browser — your photos stay private.
How to Compress a JPG Image
Reducing your JPEG file size with ImageSizr.com is fast and straightforward:
- Upload your JPG file — drag and drop, click browse, paste from clipboard (Ctrl/Cmd+V), import from a URL, or connect Google Drive, Dropbox, or OneDrive.
- Adjust the quality slider — the default is 80%, which balances quality and file size for most photos. Move it lower for smaller files or higher for better visual fidelity.
- Review the preview — use the before/after split-view to compare quality and check the resulting file size.
- Download — click Download to save your compressed JPEG.
Use the Calculate Sizes button to preview file sizes at different quality levels before committing. This makes it easy to find the sweet spot for your specific image.
JPEG Quality Tips
Getting the best results from JPEG compression depends on choosing the right quality level for your use case:
- 80% — the default setting. A good starting point that works well for most photos with minimal visible quality loss.
- 60–75% — great for web images and blog posts. Dramatically reduces file size while keeping photos looking sharp on screen.
- 85–95% — ideal for print-quality images or photos where every detail matters.
- Below 50% — noticeable artifacts may appear, especially in areas with gradients or fine detail. Use the preview to evaluate.
Each time you re-encode a JPEG at a lower quality, additional compression artifacts are introduced. For the best results, always compress from the highest-quality source image available. Learn more in our guide: choosing the right quality settings for JPG.
Understanding JPEG Compression
JPEG is a lossy format, meaning lower quality settings discard more image data to achieve smaller file sizes. Here is what you need to know:
- Compression only changes file size — your image’s pixel dimensions stay exactly the same.
- Lossy encoding — JPEG removes fine detail that is less perceptible to the human eye. At moderate quality levels, the difference is virtually invisible.
- No transparency — JPEG does not support alpha channels. If your source has transparent areas, they are filled with a background colour.
- Best for photos — JPEG excels at photographs and images with many colours, gradients, and complex textures.
For a deeper understanding of format tradeoffs, read JPG vs PNG vs WebP — when to use each.
Related Tools for JPG Workflow
- Resize your JPG image — change pixel dimensions to reduce both size and file weight.
- Crop your JPG image — remove unnecessary areas before compressing to reduce pixel count.
- Compress images in any format — use the general compressor for any supported image type.
- Compress PNG images or Compress WebP images for format-specific compression.
Read more in our image optimization guides, including how to compress images for faster web pages.
Frequently Asked Questions
How to compress a JPG image?
Upload your JPG to ImageSizr.com, adjust the quality slider (default 80%), review the before/after preview and resulting file size, and click Download to save the compressed image.
How much can I reduce the JPG file size?
It depends on the source image and quality setting. A typical photo compressed from 100% to 75% quality can see a 50–70% reduction in file size. Use the Calculate Sizes button to preview before downloading.
Will compressing my JPG make it look blurry?
At 75–80% quality, most photos show no visible difference. Below 50%, you may notice artifacts especially in areas with gradients or fine detail. Use the before/after preview to evaluate the result at your chosen setting.
Does compression reduce the image dimensions?
No. Compression only changes the file size by adjusting encoding quality. The pixel dimensions stay the same.
How do I choose the right quality level?
Start at 80% for a good balance of quality and size. Use the before/after split-view preview to compare results visually before downloading.
Is ImageSizr free to use?
Yes. ImageSizr is completely free with no account or sign-up required.
Are my images uploaded to a server?
No. All processing happens directly in your browser. Your images never leave your device, so your data stays private.
What is the maximum file size?
Each file can be up to 10 MB.