How to compress an image
Choose one JPG, PNG or WebP file. Select JPG or WebP output, set quality, and keep the original pixel dimensions unless you explicitly want fewer pixels. Press Compress image to create a new local file. The result area first shows the actual original and compressed previews, followed by exact format, pixel dimensions and byte sizes. Download result saves the file shown in that comparison.
Quality, dimensions and file size
Quality changes encoder detail without changing width or height. A lower value often produces a smaller file but may add blur, ringing or block artifacts. Resolution changes the number of pixels and is separate from quality. Reducing a 4000 × 3000 photo to 50% dimensions produces 2000 × 1500 pixels—one quarter as many pixels—so it can reduce size much more than a small quality adjustment.
JPG, PNG and WebP input
JPG, PNG and WebP are accepted as inputs, but this tool outputs only JPG or WebP. That is a real format conversion, not “lossless PNG compression.” JPG cannot store transparency, so transparent pixels are drawn on white and the interface warns before export. WebP can preserve transparency in browsers that support WebP canvas export. Animated input is treated as one decoded frame; animation is not preserved.
Two practical examples
For a large camera JPG intended for email, keep original pixels, choose JPG quality 78, compress, then inspect text and edges at full preview size. If the result is 1.4 MB from a 4.8 MB original, the tool reports the measured reduction. For a transparent PNG logo, choose WebP and keep original pixels; choosing JPG would deliberately replace transparent areas with white.
Optional target size
Enter a target such as 300 KB only when a delivery form has a strict limit. The tool searches several quality levels while keeping your chosen dimensions. It says Target met only when the actual Blob size is at or below the target. If minimum quality still produces 340 KB, it says the 300 KB target was not met; it never labels that as success. Reduce dimensions and try again if the target matters more than detail.
Limits, privacy and troubleshooting
The input limit is 20 MB, 50 megapixels and 12,000 pixels per side to reduce browser memory failures. EXIF orientation is applied by browser image decoding, while metadata is not copied to the newly encoded file. Everything remains in this tab. If the output is larger than the original, the interface reports that fact and shows zero savings. Try a lower quality, smaller dimensions or the other output format. No AI restoration, lossless guarantee or upload service is included.
Frequently asked questions
Will the tool overwrite my photo? No, it creates a separate download. Does 100 quality preserve every byte? No; JPG and WebP canvas encoding creates a new file. Why did my PNG become larger? Flat graphics can already be efficient in PNG, while a lossy photo encoder may not help at high quality. Can I force an exact number of KB? No encoder can promise every target; the measured result decides the status. Is metadata kept? No; the new image is rendered from decoded pixels.