Create a selection from a mask that selects all non-masked (non-black) areas and omits all masked (black) areas. The selection is clipped to the canvas rectangle.
Note: You can also use a selection to create a mask. For more information, see Creating Masks from Selections.
To select all non-masked areas:
Create a mask as described in Creating Masks.
On the Layer palette, select the mask layer.
Choose Selections > From Mask. The selection marque surrounds the non-masked areas.
Note: If you saved a mask to an alpha channel, you can load it as a selection by choosing Selections > Load from Alpha Channel.
Making Selections with the Freehand Tool
Making Selections with the Magic Wand Tool
Making Selections with the Selection Tool