About JPEG format


    The JPEG format supports 24-bit color and preserves the broad range and subtle variations in brightness and hue found in photographs and other continuous-tone images. JPEG is supported by most browsers.

    JPEG compresses file size by selectively discarding data. Because it discards data, JPEG compression is referred to as lossy. A higher quality setting results in less data being discarded, but the JPEG compression method can degrade sharp detail in an image, particularly in images containing type or vector art.

    Note: You should always save JPEG files from the original image, not from a previously saved JPEG. Artifacts, such as wave-like patterns or blocky areas of banding, are added to a file each time you save in JPEG format.

    You can create a progressive JPEG file. A browser immediately starts rendering a progressive JPEG when it receives the first data representing the image. As the remainder of the progressive JPEG file is received, the image increases in resolution.

    The JPEG format does not support transparency, but you can simulate the effect of background transparency by specifying a Matte color that matches the Web page background color.