Compress Image — Reduce JPG, PNG & WebP File Size Free Online
Reduce your image file size instantly — entirely in your browser, with no file upload and no server involved. Supports JPG, PNG, and WebP. Adjust compression quality from 5% to 100%, choose your output format, and see a real-time before/after size comparison with a visual gauge showing exactly how much space you saved.
Compression Result
How to Compress an Image
Alfreto's image compressor uses the browser's built-in HTML5 Canvas API to re-encode your image at a lower quality level — entirely on your device. No file is ever sent to any server. The result is a smaller image file that looks nearly identical to the original, ready to download in seconds.
Step 1 — Upload Your Image
Click Choose Image or drag and drop a JPG, PNG, or WebP file into the drop zone. The original image appears immediately in the right panel so you can see what you are working with. The file size is displayed next to the filename.
Step 2 — Set Quality and Output Format
Use the Quality slider to set the compression level from 5% (maximum compression, smallest file) to 100% (no compression). Then select your preferred output format:
- JPEG — Best choice for photographs and images with many colors. Produces the smallest file sizes with lossy compression. Quality slider has full effect.
- PNG — Best for screenshots, logos, and images with flat colors or transparency. Uses lossless compression — the quality slider does not affect PNG output size.
- WebP — Google's modern image format. Produces files 25–35% smaller than JPEG at the same quality. Supported by all modern browsers (Chrome, Edge, Firefox, Safari).
Recommended settings by use case: For sharing on social media or email — 70–80% JPEG. For website images — 60–75% WebP. For documents or screenshots — PNG (lossless). For archiving originals — 90–95% JPEG.
Step 3 — Compress and Download
Click Compress. The tool processes your image through the browser's canvas encoder and shows a circular gauge with the percentage of file size saved. Below the gauge you will see three stats: original size, compressed size, and bytes saved. A side-by-side visual preview of the original vs. compressed image is also shown so you can judge quality visually before downloading.
If the result looks good, click Download to save the compressed image to your device. The filename is automatically suffixed with _compressed so your original file is not overwritten.
When to Use This Tool
- Email attachments — Many email clients reject attachments over 5–10 MB. Compressing photos to JPEG at 75% typically reduces a 4 MB photo to under 500 KB.
- Website optimization — Large images are the single biggest cause of slow page load times. Serving compressed WebP images instead of original JPEGs can reduce image payload by 60–70%.
- WhatsApp and messaging apps — Compressing photos before sending preserves detail that apps would otherwise degrade with their own auto-compression.
- Cloud storage — Reduce the storage footprint of large photo collections before uploading to Google Drive, iCloud, or Dropbox.
- Form uploads — Many online forms and portals have file size limits. Compress images to meet requirements without resizing dimensions.
Frequently Asked Questions
Is my image uploaded to a server when I compress it?
No — your image never leaves your device. The tool uses the browser's built-in HTML5 Canvas API to re-encode the image entirely in JavaScript. No data is transmitted over the internet at any point. This makes the tool completely safe for private, sensitive, or confidential images such as ID documents, medical records, or personal photos.
What quality setting should I use?
For most photographs shared via email or social media, 70–80% delivers an excellent balance — typically reducing file size by 60–75% with barely visible quality loss. For website images, 60–75% WebP is the sweet spot. For archiving or printing, use 90–95% JPEG to preserve fine detail. For quick previews or thumbnails, 50–60% is usually sufficient.
Which image formats are supported?
You can upload JPG, PNG, or WebP images. You can also convert the output to a different format — for example, upload a large PNG and save it as WebP for a dramatically smaller file, or convert a WebP to JPG for maximum compatibility with older systems.
Why doesn't PNG compression reduce the file size much?
PNG is a lossless format, meaning it preserves every pixel exactly. The quality slider only affects lossy formats (JPEG and WebP) and has no effect on PNG output. If you need a smaller file from a PNG source, select JPEG or WebP as the output format — this will typically reduce the file size by 50–80%.
What is WebP and when should I use it?
WebP is a modern image format developed by Google, introduced in 2010. It uses advanced compression algorithms that produce files roughly 25–35% smaller than JPEG at equivalent visual quality, and also supports transparency like PNG. All modern browsers — Chrome, Edge, Firefox, and Safari — fully support WebP. It is the recommended format for all web images.
Will the image dimensions change after compression?
No. This tool only adjusts the compression quality and output format — image dimensions are preserved exactly. If you need to reduce an image's width or height, use a dedicated resize image tool. Resizing and compressing together is the most effective way to reduce file size.
Why is my compressed file larger than the original?
This can happen when you compress an already-compressed image (e.g., a JPEG) and convert it to PNG, or when you use a very high quality setting (90%+) on a small original file. Try selecting JPEG or WebP output and lowering the quality to 70–80%. WebP almost always produces the smallest output for any input format.
Can I compress multiple images at once?
Currently the tool processes one image at a time. To compress multiple images, repeat the process for each file. Because everything happens in-browser with no upload wait time, each image typically takes under 2 seconds to compress, making batch work quick even one-by-one.
Why Use Alfreto to Compress Images?
Most image compressors upload your files to a remote server, introduce waiting time, and leave your images stored on someone else's infrastructure. Alfreto's compressor works entirely in your browser — the compression is instant, completely private, and free without any limits.