Clicking the Work with regions button 
brings up the work with region window. This gives you complete control over how the image is compressed and gives you access to advanced compression facilities such as smoothing.
The region window
The region window shows a black and white version of the image. As you apply an effect (for example MagiCompression) to the image the effected regions are colored. The darker the color the more the effect has been applied.
You can change the effect that the window displays by pressing one of the tabs at the top of the window. For example if you press the Smoothing tab then the window displays regional smoothing.
The lower slider on the Compress Image Control Palette changes to show a slider for the effect that has been selected. In the above example the slider will change to show the amount of smoothing to be applied.
The Mouse
The mouse is used to apply or remove the selected effect. The left mouse button applies the selected effect at the level determined by the position of the slider. The right mouse button removes the effect (i.e. sets it to zero).
N.B. You can use the mouse on any of the image windows, not just the region window.
The drawing tools
You can select between four tools from the Tool palette:
 | Rectangle | The rectangle tool lets you select a rectangle |
 | Freehand | The freehand tool lets you select an any shaped region |
 | Brush | The Brush tool allows you to paint optimization. You can alter the setting for the Brush using the Brush Settings Palette |
 | Line | The Line tool draws a line in the currently selected Brush Size and Style |
The region tools
The region tools are:
 | Lock region | This tool causes the last selected region to be locked on the image. After that all subsequent moves of the effect slider will be applied uniformly to the locked region. |
 | Select Whole Image | This button is similar to Lock region but selects and locks the whole image so that effects can be applied to the the whole image. |
 | Invert Region | Inverts the currently locked region |
The region tools are useful for interactively trying different values of an effect on a selected region of the image. For example a face in an image could be selected using the freehand tool. The Lock region button is pressed and the MagiCompress slider moved until the best value of MagiCompression for the face is found.