What this tool does
Reduce image file size in your browser by re-encoding it with an adjustable quality setting. The original file never leaves your device, and you can compare dimensions and approximate output size before saving the compressed result.
Image compression can improve page speed and reduce upload time, but excessive compression creates visible artifacts. Photos often compress well as JPEG or WebP, while graphics with transparency may need PNG or WebP. Always keep the original file separately if it has long-term value.
Useful for
- Prepare photos for websites and blog posts.
- Reduce large screenshots before sharing or uploading.
- Experiment with quality settings without sending files to an external conversion service.
How to use it
- Choose an image from your device.
- Select the output format and quality level.
- Generate the compressed preview and compare file sizes.
- Save the result only when visual quality remains acceptable.
Practical tips
- Resize oversized images before or during compression for bigger savings.
- Use WebP when your publishing environment supports it.
- Avoid repeatedly recompressing the same lossy image.
- Metadata may not be preserved when the browser re-encodes the image.
Frequently asked questions
Are my images uploaded to ToolsDiary?
No. The image is decoded and re-encoded in your browser.
Why can a PNG become larger after compression?
PNG is lossless and behaves differently from photo-oriented lossy formats. A WebP or JPEG output may be smaller for photographic content.
Does the tool preserve EXIF metadata?
Browser canvas export usually does not preserve the original EXIF metadata. Keep the original if metadata matters.