JPEG
Todo: Remake File:JPEG_Quality_Comparison.jpg to be a more practical showcase of JPEG's quality levels.
JPEG (more commonly seen with the extension .jpg) is an image format which uses lossy compression to reduce the file size of the image. This results in file sizes that are significantly smaller than uncompressed formats such as BMP or TGA. Lossy compression affects image quality, but higher quality JPEGs will have nearly imperceptible artifacts. JPEGs are suitable for photographs and screenshots, but are not preferred for textures or diagrams.
Source
Used for screenshots in many games...[Clarify]