1. Open Photoshop. Open the image to
apply uneven edge border.
2. Select Rounded Corner Tool from the toolbox (marked
red in the fig.).
3. Keep "Paths" option selected as shown
in the fig (marked in green).
4. Drag the rounded corner rectangle in the middle
of the image as shown the the picture.
5. Go to Path Tab and click "Load path as a selection"
to convert the path into selection.
6. Go to Channels tab. Create new channel. Fill white
color and deselect the selection with CTRL+ D.
7. Filters > Brush Strokes
Spray Radius: 10
8. Go to Layers Tab and create new layer. Keep the
new layer selected.
9. Select > Load Selection (Select Alpha1 from channel drop down and check Invert)
10. Fill white color using Alt + Del. and deselect
with CTRL + D.