1.OPEN AN IMAGE

Open the image that you want make a brush preset.I’m going to make a brush of this image of flower.

step 1

2.CUT THE IMAGE

Cut the image with pen tool or magic tool.
step 3
With that, We have this result.
step 4

3.EDIT MENU

Go to EDIT>DEFINE BRUSH PRESET and give it a name and press OK…
step 5

4.TESTING

Open new document with any background color, Select brush tool and select the brush you’ve just made and apply it. Your brush is now ready.
step 6