Compress Image

Image compression is the process of reducing an image file's size in bytes, usually by storing it with less detail than the original. This tool uses lossy compression for JPG and WebP: lowering the quality slider discards fine detail that is hard to see and shrinks the file, while the width and height in pixels stay the same. PNG is lossless, so the slider has no effect on it. To save space on a PNG photo, convert it to JPG or WebP. A quality of 70 to 80 percent is a common starting point for photos. After each change the tool shows the original size, the new size and the percentage saved, so you can lower the quality until you notice a difference and then step back up. Because everything happens in your browser, the image is never uploaded to a server and nothing is kept once you close the page.

JPG and WebP use lossy compression: lowering the quality removes detail the eye barely notices and shrinks the file. A setting around 70 to 80 percent is often a good balance.

PNG is lossless, so the quality slider does not apply to it. To shrink a PNG photo, convert it to JPG or WebP.

The numbers below are an illustration of the arithmetic, not a measurement of a real file. Results depend on the image, so always check the sizes the tool shows you. Imagine a photo that is 2.4 MB (2,400 KB). You lower the quality slider and the tool reports a new size of 600 KB. The saving is 2,400 minus 600, which is 1,800 KB. Divided by the original 2,400 KB, that is 0.75, so the file is 75 percent smaller, or one quarter of its original size.

Now imagine the same photo is 4000 by 3000 pixels, which is 12,000,000 pixels. If you first reduce it to 2000 by 1500 pixels, you keep only 3,000,000 pixels, exactly a quarter, before any quality change is applied. Fewer pixels means less data to store, which is why changing the dimensions often saves more than the quality slider alone.

To follow this workflow, first set the dimensions with the [resize image](resize-image) tool, then bring the result here and lower the quality until you just start to see a difference. Step back up one notch and download the file. Because the tool shows the original and new size after every change, you can see at once whether the extra step was worth it for your image.

**JPG** is the long-standing choice for photographs. It uses lossy compression, works in practically every browser, app and device, and does not support transparency. When you save as JPG, this tool fills transparent areas with white.

**PNG** is lossless and keeps every pixel exactly, with support for transparency. That makes it a good fit for screenshots, logos, icons and graphics with sharp edges and flat colors. For photographs, PNG files are usually much larger than JPG or WebP, and the quality slider is not available for PNG output.

**WebP** supports both lossy and lossless compression as well as transparency, and modern browsers can display it. For many images it produces smaller files than JPG at similar visual quality. If you load a PNG, this tool preselects WebP, because re-saving a PNG as PNG rarely makes it smaller and WebP keeps transparency.

Compression and resizing work best together. Compression lowers the number of bytes used per pixel, while resizing lowers the number of pixels. A photo from a modern phone is often far larger than a web page or an email ever displays, so reducing the dimensions first and compressing second usually gives the smallest file for a given level of visible quality.