Optimization options for JPEG format

JPEG is the standard format for compressing continuous-tone images such as photographs. Optimizing an image as a JPEG relies on lossy compression, which selectively discards data. (See About JPEG format.)

Quality

Choose an option from the Quality menu or specify a value in the Quality text box. The higher the Quality setting, the more detail the compression algorithm preserves. However, using a high Quality setting results in a larger file size than using a low Quality setting. View the optimized image at several quality settings to determine the best balance of quality and file size.

Optimized

Select Optimized to create an enhanced JPEG with a slightly smaller file size. The Optimized JPEG format is recommended for maximum file compression; however, some older browsers do not support this feature.

Progressive

Select Progressive to create an image that displays progressively in a Web browser. The image will display as a series of overlays, enabling viewers to see a low-resolution version of the image before it downloads completely. The Progressive option requires use of the Optimized JPEG format.

Blur

Specify the amount of blur to apply to the image. This option applies an effect identical to that of the Gaussian Blur filter while compressing the file more, resulting in a smaller file size. A setting of 0.1 to 0.5 is recommended.

ICC Profile

Select ICC Profile to preserve the ICC profile of the artwork with the file. ICC profiles are used by some browsers for color correction. This option is only available after you've saved an image with an ICC profile--it is not available for unsaved images. (See Using ColorSync with JPEG images (Mac OS).)

Matte

Specify how to optimize transparent pixels in the image:

• To fill fully transparent pixels and blend partially transparent pixels with a matte color, click the Matte color swatch and select a color in the color picker. Alternatively, choose an option from the Matte pop-up menu: Eyedropper (to use the color in the eyedropper sample box), White, Black, or Other (to use the color picker).
• To make all pixels with greater than 50% transparency fully transparent and all pixels with 50% or less transparency fully opaque, choose None from the Matte pop-up menu.