Image Compression Policy Settings

The Image compression section contains settings that enable you to remove or alter compression. When client connections are limited in bandwidth, downloading images without compression can be slow.

Extra color compression

This setting controls the degree of extra color compression used on images delivered over client connections thta are limited in bandwidth, improving responsiveness by reducing the quality of displayed images. When enabled Extra Color Compression is applied only when the client connection bandwidth is below the Extra Color Compression Threshold value. When the client connection bandwidth is above the threshold value or Disabled is selected, Extra Color Compression is not applied.

Related Policy Settings

Extra color compression threshold

Extra color compression threshold

This setting represents the maximum bandwidth in kilobits per second for a connection below which extra color compression is applied. If the client connection bandwidth drops below the set value, extra color compression, if enabled, is applied. By default, the threshold value is 2000 kilobits per second.

Related Policy Settings

Extra color compression

Lossy compression levelThis setting controls the degree of lossy compression used on images delivered over client connections that are limited in bandwidth. In such cases, displaying images without compression can be slow. By default, medium compression is selected.

For improved responsiveness with bandwidth-intensive images, use high compression. Where preserving image data is vital; for example, when displaying X-ray images where no loss of quality is acceptable, you may not want to use lossy compression.

Related Policy Settings

• Lossy compression threshold value
• Progressive compression level
• Progressive heavyweight compression level

Lossy compression threshold valueThis setting represents the maximum bandwidth in kilobits per second for a connection to which lossy compression is applied. By default, the threshold value is 2000 kilobits per second.

Adding the Lossy compression level setting to a policy and including no specified threshold can improve the display speed of high-detail bitmaps, such as photographs, over a LAN.

Related Policy Settings

Lossy compression level

Progressive compression levelThis setting provides a less detailed but faster initial display of images. The more detailed image, defined by the normal lossy compression setting, appears when it becomes available. Use very high or ultra high compression for improved viewing of bandwidth-intensive graphics such as photographs.

For progressive compression to be effective, its compression level must be higher than the Lossy compression level setting; by default, progressive compression is not applied.

Note: The increased level of compression associated with progressive compression also enhances the interactivity of dynamic images over client connections. The quality of a dynamic image, such as a rotating three-dimensional model, is temporarily decreased until the image stops moving, at which time the normal lossy compression setting is applied.

Related Policy Settings

• Progressive compression threshold value
• Lossy compression level
• Progressive heavyweight compression

Progressive compression threshold valueThe maximum bandwidth in kilobits per second for a connection to which progressive compression is applied. This is applied only to client connections under this bandwidth. By default, the threshold value is 1440 kilobits per second.

Related Policy Settings

Progressive compression level

Progressive heavyweight compressionThis setting enables or disables reducing bandwidth beyond progressive compression without losing image quality by using a more advanced, but more CPU-intensive, graphical algorithm. By default, progressive heavyweight compression is disabled.

If enabled, heavyweight compression applies to all lossy compression settings. It is supported on the Citrix online plug-in but has no effect on other plugins.

Related Policy Settings

• Lossy compression level
• Progressive compression level