Bitmaps

Bitmap & Fill Galleries are described in Photo Handling and Fills.

When you select a transparency type of Bitmap, a default bitmap is initially used. Click on Bitmap Name in the transparency InfoBar, or use the Bitmap or Fill Galleries to change the bitmap used (click the Transp button in the gallery or drag-and-drop from the gallery).

By default, the lighter colors in a bitmap are the most transparent (you can, of course, alter the relative amounts of transparency later).