Use the Quick Selection tool to easily "paint" a selection as you drag over an area. The selection automatically finds and follows defined edges in the image.
Select the Quick Selection tool.
In the Options bar, chose either New Selection, Add to Selection, or Subtract from Selection.
Click the Brush menu in the Options bar to set a brush size.
Choose from the following options:
Sample All Layers: makes a selection based on all layers in an image.
Auto-Enhance: reduces roughness and blockiness in the selection boundary.
Paint over the part of the image you want to select. As you paint near the edges of a shape, the selection area extends to follow the shape edge.
After making the first selection, the tool's option changes automatically to Add to Selection. Continue painting to select more pixels.
To remove pixels from a selection, click the Subtract from Selection option in the Options bar, then drag over an area that is already selected.