How does browser-based compression work?

The tool draws your image onto a canvas and re-encodes it as JPEG or WebP at a lower quality setting, reducing file size while preserving visual appearance.

Can I compress PNG losslessly?

True lossless PNG compression requires dedicated algorithms not available in the browser canvas API. PNG output through canvas uses a fixed compression level.

How much can images be compressed?

JPEG images can typically be reduced to 30–60% of their original size at 70–80% quality with minimal visible quality loss. WebP offers better compression at the same quality.

Is my image uploaded to a server?

No. All compression happens locally in the browser. Your image never leaves your device.

Does the quality slider affect PNG files?

JPEG and WebP use the quality setting. PNG output ignores the slider because the canvas API exports PNG without a quality parameter.

Which output format should I choose?

JPEG is usually best for photographs, PNG for sharp graphics or transparency, and WebP for smaller modern web images.

Can compression preserve transparency?

PNG and WebP preserve transparency. JPEG does not support an alpha channel, so transparent areas may render with a solid background.

Is there a file size limit?

Very large images can exceed browser memory or canvas limits. If compression fails, reduce image dimensions first with the image resizer.

Does compression reduce image dimensions?

No. The compressor keeps the image's natural width and height. Use an image resizer when you need to change dimensions.

Which image format produces the smallest file?

Results depend on image content and settings. WebP is often smallest for web graphics, JPEG is efficient for photos, and PNG is usually largest when lossless detail or transparency is required.

Image Tools

Image Compressor

Compress JPEG, PNG, or WebP images with an adjustable quality slider. Shows exact file size savings before download — processed in your browser, nothing uploaded.

JPEG / PNG / WebP
Quality Slider
Size Savings %
No Upload
Browser-only

Image file

Compress images in your browser

Image compression reduces the bytes needed to store or deliver a picture. This tool decodes a selected image into a browser canvas, re-encodes it as JPEG, WebP, or PNG, and creates a local download. Your file is not uploaded to a server.

Choose an image, select an output format, set quality for lossy formats, and click Compress image. The preview and size comparison help you check the result before downloading.

JPEG, PNG, and WebP compared

Format	Compression	Transparency	Best for
JPEG	Lossy	No	Photos and broad compatibility
PNG	Lossless canvas encoding	Yes	Logos, screenshots, and diagrams
WebP	Lossy	Yes	Smaller modern web images

JPEG

JPEG is effective for photographs with gradients and natural detail. Lower quality normally produces a smaller file, but aggressive settings can create blocking around text and edges. JPEG cannot retain transparent pixels.

PNG

PNG preserves sharp edges and transparency. The quality slider does not affect PNG because the Canvas API does not accept a quality argument for PNG output. PNG may remain larger than JPEG or WebP for photographic content.

WebP

WebP often produces smaller files than JPEG at similar visual quality and can preserve transparency. Check target-browser support when preparing assets for older applications.

How browser compression works

The browser decodes the selected image.
Canvas receives the image at its natural pixel dimensions.
Canvas exports a new Blob in the chosen MIME type.
The Blob becomes a temporary local URL for preview and download.

Compression changes encoding, not dimensions. Re-encoding an already compressed JPEG can add artifacts, so keep an original source for later edits.

canvas.toBlob((blob) => {
  // Preview or download the compressed Blob.
}, "image/webp", 0.8);

from PIL import Image

Image.open("source.jpg").save("compressed.webp", "WEBP", quality=80)

magick source.jpg -quality 80 compressed.jpg

Choosing a quality setting

Quality values around 70–85% are a practical starting point for JPEG and WebP photographs. Use higher quality for product images or detailed illustrations, and lower quality when bandwidth or storage matters more than fine texture. Always inspect the preview: flat graphics, small text, and gradients reveal artifacts sooner than busy photographs.

Privacy and file limits

Processing happens locally in browser memory. No account or upload is required, and the original file is never modified. Very large images may exceed device memory or browser canvas limits; resizing the source first can help.

Animated GIFs are generally decoded as one frame by canvas, so compression creates a static output image. Supported source formats also depend on the browser.

Frequently Asked Questions

How does browser-based compression work?: The tool draws your image onto a canvas and re-encodes it as JPEG or WebP at a lower quality setting, reducing file size while preserving visual appearance.
Can I compress PNG losslessly?: True lossless PNG compression requires dedicated algorithms not available in the browser canvas API. PNG output through canvas uses a fixed compression level.
How much can images be compressed?: JPEG images can typically be reduced to 30–60% of their original size at 70–80% quality with minimal visible quality loss. WebP offers better compression at the same quality.
Is my image uploaded to a server?: No. All compression happens locally in the browser. Your image never leaves your device.
Does the quality slider affect PNG files?: JPEG and WebP use the quality setting. PNG output ignores the slider because the canvas API exports PNG without a quality parameter.
Which output format should I choose?: JPEG is usually best for photographs, PNG for sharp graphics or transparency, and WebP for smaller modern web images.
Can compression preserve transparency?: PNG and WebP preserve transparency. JPEG does not support an alpha channel, so transparent areas may render with a solid background.
Is there a file size limit?: Very large images can exceed browser memory or canvas limits. If compression fails, reduce image dimensions first with the image resizer.
Does compression reduce image dimensions?: No. The compressor keeps the image's natural width and height. Use an image resizer when you need to change dimensions.
Which image format produces the smallest file?: Results depend on image content and settings. WebP is often smallest for web graphics, JPEG is efficient for photos, and PNG is usually largest when lossless detail or transparency is required.

Disclaimer

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Compress images in your browser

Choose an image, select an output format, set quality for lossy formats, and click Compress image. The preview and size comparison help you check the result before downloading.

JPEG, PNG, and WebP compared

Format	Compression	Transparency	Best for
JPEG	Lossy	No	Photos and broad compatibility
PNG	Lossless canvas encoding	Yes	Logos, screenshots, and diagrams
WebP	Lossy	Yes	Smaller modern web images

JPEG

PNG

WebP

WebP often produces smaller files than JPEG at similar visual quality and can preserve transparency. Check target-browser support when preparing assets for older applications.

How browser compression works

The browser decodes the selected image.
Canvas receives the image at its natural pixel dimensions.
Canvas exports a new Blob in the chosen MIME type.
The Blob becomes a temporary local URL for preview and download.

Compression changes encoding, not dimensions. Re-encoding an already compressed JPEG can add artifacts, so keep an original source for later edits.

canvas.toBlob((blob) => {
  // Preview or download the compressed Blob.
}, "image/webp", 0.8);

from PIL import Image

Image.open("source.jpg").save("compressed.webp", "WEBP", quality=80)

magick source.jpg -quality 80 compressed.jpg

Choosing a quality setting

Privacy and file limits

Animated GIFs are generally decoded as one frame by canvas, so compression creates a static output image. Supported source formats also depend on the browser.