Reduce image file size with adjustable quality. See before/after comparison. 100% private - no server upload.
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Click to upload or drag & drop an image
PNG, JPG, WebP supported
Compression Settings
Original
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Compressed
Press "Compress Image" to see result
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About Image Compressor
Compress images instantly in your browser. Adjust quality level and choose between JPEG, WebP, and PNG output. WebP format typically achieves 25–35% smaller files than JPEG at the same quality. No file is ever uploaded to a server - everything runs locally.
How to Use
Upload your image by clicking or dragging it onto the upload area.
Choose an output format - JPEG for photos, WebP for best compression, PNG for lossless.
Click Compress Image to see the before/after file size comparison.
Click Download to save the compressed image.
How It Works
The tool draws your image onto an HTML5 Canvas and re-encodes it using the browser's built-in codec at your chosen quality level. PNG compression is lossless, so the quality slider only affects JPEG and WebP outputs.
Frequently Asked Questions
For most use cases, 70–85% quality offers a good balance between file size and visual quality. For web images where fast loading matters, 60–75% is often sufficient. For print or archiving, use 90%+.
PNG is a lossless format - it cannot discard pixel data. The quality slider has no effect on PNG output. To significantly compress a PNG photo, switch to JPEG or WebP format instead.
WebP is a modern image format developed by Google. It typically produces files 25–35% smaller than JPEG at equivalent visual quality, and also supports transparency like PNG. All modern browsers support WebP.
No. This tool only changes the encoding quality and format, not the pixel dimensions. The output image will be the same width and height as the original. Use the Image Resizer tool if you also need to change dimensions.
Only PNG compression is lossless. JPEG and WebP compression at less than 100% quality are lossy - they remove some image data to reduce file size. At quality levels of 80%+, the difference is usually imperceptible to the human eye.
About Image Compressor — Free Online Image Compression Tool
This free online image compressor reduces the file size of your images without significant visible quality loss — all processed locally in your browser with no server upload required. Smaller images load faster, score better on Google's Core Web Vitals assessment, consume less storage and bandwidth, and make your website or app feel more responsive. Whether you are a web developer optimising a site, a blogger preparing images for upload, or someone reducing photo sizes before sending by email, this image compressor tool handles it in seconds.
Image file size is one of the most impactful factors in web page performance. According to HTTP Archive data, images account for roughly 50% of the average web page's total transfer size. Google's PageSpeed Insights and Core Web Vitals framework directly penalise pages with oversized images — specifically through the Largest Contentful Paint (LCP) metric, which measures how long the main image on a page takes to load. Compressing images before uploading them to a website, CMS, or social platform is one of the highest-return optimisations available to content creators and developers. This image compressor online tool makes that optimisation accessible to everyone, not just those with access to professional design software.
How to Use the Image Compressor
Upload an image by clicking Choose Image or dragging and dropping it into the upload area. JPEG, PNG, WebP, GIF, and BMP files are all supported.
Adjust the Quality slider. Lower quality = smaller file size with more compression; higher quality = larger file but better visual fidelity. The default 80% quality is a good starting point for most web images.
The tool instantly shows the original file size, compressed file size, and the percentage reduction achieved. Adjust the slider to find your preferred quality-to-size balance.
Click Download to save the compressed image to your device.
How the Compression Works
The image is drawn onto an HTML5 canvas element, then re-exported as JPEG using the canvas API's toDataURL('image/jpeg', quality) method with the specified quality value (0.0–1.0). JPEG compression is lossy — it removes image data that is imperceptible at normal viewing distances by reducing colour precision in high-frequency detail areas. At quality 80% (0.8), file sizes are typically 60–75% smaller than the original with no visible quality loss when viewed on screen at standard resolution.
Example Results
A 3MB JPEG hero image at quality 80 typically compresses to 400–600 KB. At quality 70 it may reach 250–400 KB. For most web images, 75–85% quality is the sweet spot between file size and visual fidelity at screen viewing distances.
Tips for Getting the Best Image Compression Results
Start at 80% quality and adjust from there: The 80% quality setting (the tool's default) eliminates the majority of unnecessary image data while preserving all visually perceptible quality at normal screen viewing distances. Only lower the quality further if you need a specific file size target and the visual difference is acceptable for your use case. Conversely, increase to 90% for images where fine detail matters — product photography, medical images, or high-resolution portfolio work.
Resize images before compressing: Compression reduces quality per pixel, but if your image is larger in dimensions than it needs to be, you can achieve much greater file size reductions by resizing first. A 4000×3000 px photograph that will be displayed at 800×600 px contains 25× more pixel data than needed — resizing it before compressing can reduce the file to 1/25th of its original size before compression even runs. Use the Image Resizer tool on this site to resize first, then compress.
Use JPEG (this tool) for photographs, PNG for graphics: JPEG compression works exceptionally well on photographic content with smooth colour gradients. For graphics with flat colours, text, line art, or transparent backgrounds (logos, icons, screenshots), PNG's lossless compression often produces smaller files than JPEG at equivalent quality. This compressor converts all inputs to JPEG — if you need lossless compression for a PNG graphic, use a dedicated PNG tool instead.
Batch compress before uploading to a CMS: Content management systems like WordPress, Squarespace, and Shopify often perform their own image optimisation, but they work better when starting from already-compressed files. Compressing images to under 200 KB before uploading to a CMS gives the platform's own optimisation pipeline better starting material and reduces storage usage in your media library.
Check compressed images at full size before publishing: After downloading a compressed image, open it at 100% zoom to verify that the compression artefacts are acceptable for your use case. JPEG compression at very low quality settings introduces visible blockiness in smooth colour areas — always visual-check the compressed output before it goes live on a high-visibility page.
Frequently Asked Questions about Image Compressor
For web images displayed on screen at standard resolution, 75–85% quality is generally the optimal range — it achieves 60–75% file size reduction with no visually perceptible quality loss when viewed at normal distances. Quality settings of 90–95% are appropriate for archival images, print-destined files, or product photography where fine detail must be preserved. Settings below 70% produce visible compression artefacts in smooth colour gradients and are only appropriate for thumbnail images or cases with strict file size budgets.
Yes — PNG files can be uploaded to this image compressor. However, the tool converts all files to JPEG format during compression, which means PNG transparency (alpha channel) is not preserved — transparent areas become white or black in the output. If you need to preserve PNG transparency, JPEG is not the right format for the output. For lossless PNG compression that preserves transparency, use a dedicated PNG optimiser tool. For opaque PNG photographs, converting to JPEG with this compressor often produces significantly smaller files than the original PNG.
Images that are already heavily compressed — such as screenshots saved as JPEG, JPEG images that have been re-saved multiple times, or very small images — have limited additional compression potential because most of the reducible data has already been removed. In these cases, lowering the quality slider further may produce visible artefacts before achieving significant size reduction. PNG screenshots in particular may actually increase in file size when converted to JPEG, because PNG's lossless compression is already highly efficient for screen-captured content with flat colours and text.
No — all image compression happens locally in your browser using the HTML5 Canvas API. Your image file never leaves your device and is never uploaded to any server. This is particularly important for sensitive or confidential images — personal photographs, medical images, proprietary product photos, or client materials. The entire compression process runs in your browser tab with no network requests involving your image data. You can verify this by turning off your internet connection after the page loads — the compressor will continue to work without any network access.
The image compressor accepts any image format that your browser can read: JPEG, PNG, GIF (first frame only), WebP, BMP, and SVG. All formats are drawn onto an HTML canvas and re-exported as JPEG with the selected quality setting. This means the output is always JPEG regardless of the input format — if your input is PNG with transparency, the transparent areas will be filled with white in the JPEG output. The input file can be any size; the browser handles the file reading with the FileReader API locally.
Yes — this image compressor online is completely free. No account is required, no subscription is needed, and there are no file size limits or usage quotas. You can compress as many images as you need without any restriction. The tool works in any modern browser on desktop and mobile, and since all processing happens locally, it works even on slow internet connections after the page has loaded. Simply upload your image, adjust the quality slider, and download the compressed result.
JPEG compression works by dividing the image into 8×8 pixel blocks, applying a Discrete Cosine Transform (DCT) to each block to convert pixel values into frequency components, and then discarding high-frequency components that are less perceptible to human vision. The quality setting controls how aggressively high-frequency data is discarded — lower quality removes more data, producing smaller files with more visible blockiness and colour banding. JPEG was designed specifically for photographic content with smooth colour gradients, which is why it is less suitable for graphics with sharp edges, text, or solid colour areas.
Yes — the image compressor is fully mobile-compatible. You can upload images directly from your phone's camera roll or file storage by tapping the upload area. The quality slider, before/after size comparison, and download button are all touch-accessible on smartphone and tablet screens. The tool works on iOS Safari and Android Chrome without any app installation. Compressed images are downloaded to your device's default download location. On iOS, you may be prompted to save the image to your Photos library or Files app.