MACROMEDIA STUDIO 8-EXPLORING STUDIO 8 Manual page 208

208 Tutorial: Creating a Page Banner
4. On the canvas, draw and position the rounded rectangle inside
the banner.
The area that falls outside the rounded rectangle will be black, forming
the banner's outline.
Use the blue selection points to adjust the size of the shape. Use the
yellow diamond-shaped control points to adjust the roundness of
the corners.
5. With the rounded rectangle still selected, select Edit > Cut.
6. In the Layers panel, select the background photo (called "Bitmap") on
the Background layer.
You want to apply the mask to this object.
7.
Select Edit > Paste As Mask to apply the mask to the photo.
On the canvas, the area covered by the rounded rectangle is visible. The
area outside it is masked.
In the Layers panel, a mask thumbnail appears next to the background
photo. The green highlight around the mask thumbnail indicates that
it is selected.
8.
Save your work.