Compress images with precise quality control -- free, private, runs in your browser
Image compression reduces the file size of an image by encoding its pixel data more efficiently. Every digital image is a grid of pixels, and each pixel stores color information. Without compression, a 4000x3000 photograph at 24-bit color depth would take up roughly 36 megabytes. Compression algorithms find patterns and redundancies in this data to represent the same image in far fewer bytes.
There are two stages where compression happens: during encoding (when the file is saved) and optionally during resizing (when the pixel count is reduced). This tool gives you control over both.
Lossy compression permanently discards some image data that is difficult for the human eye to notice. JPG and WebP (in lossy mode) use this approach. The quality slider controls how aggressively data is discarded -- lower values mean smaller files but more visible artifacts like banding, blurring, and blockiness around edges.
Lossless compression reduces file size without losing any data. PNG uses lossless compression. The original image can be perfectly reconstructed from the compressed file. The trade-off is that lossless files are typically much larger than lossy equivalents, especially for photographs.
For photographs and complex images, lossy compression at quality 75-85 usually achieves a 60-80% file size reduction with no perceptible quality loss. For graphics, logos, and screenshots with large flat-color areas, lossless PNG often compresses well on its own.
The quality slider ranges from 1 (maximum compression, lowest quality) to 100 (minimum compression, highest quality). Here is a practical guide:
The live file size preview updates as you move the slider, so you can find the exact balance between quality and file size before downloading.
For web images, quality 75-80 in WebP or JPG format gives the best balance of visual quality and file size. For print, use 90 or above. The live preview lets you compare the estimated output size as you adjust the slider.
WebP produces the smallest files for photographs -- typically 25-35% smaller than JPG at the same visual quality. JPG is widely compatible and compresses photos well. PNG is lossless and best for graphics with transparency. Choose based on your needs: WebP for web performance, JPG for broad compatibility, PNG for quality preservation.
Yes. Resizing an oversized image to your actual display dimensions before compressing yields much better results than compression alone. A 4000px-wide image displayed at 800px is wasting bandwidth on pixels that are never shown. Resize first, then compress for the smallest file at the best quality.
Yes. Each round of lossy compression introduces additional artifacts. This is called generation loss. If possible, start from the highest-quality original. Avoid repeatedly compressing the same image.