Use Contrast to adjust both the contrast and brightness of an image.

For example, if you have the following image:

unprocessed image

You can use the Contrast transformation to change it to:

Icontrast applied

If you add the IMQuery transformation to a policy, use the im variable, and select Contrast, you can use a query string to add contrast to any image using this policy. See Syntax and Examples for the syntax for the query string parameter.