Human: What is the difference between a jpeg and a png file? Assistant: 
The key difference between a JPEG and a PNG file is how they are compressed. JPEGs use lossy compression, meaning that some image detail is lost when the file is compressed, while a PNG uses lossless compression, meaning that no image detail is lost when the file is compressed. JPEGs typically take up less space than a PNG because they are more heavily compressed, while PNGs offer better image quality than JPEGs.