1. Open photoshop and Create a new file. 8px wide and 1 px in height.
2. zoom it to get a closer look, and using the retangle marquee tool select 6 pixels, leaving 1 px on each side.
3. fill the selection with the color you want the ‘stich’ or ‘dash’ to be.
4. Click Edit –> Define Patteren
5. Now, on the document you want the ‘stitch to be, create a selection using ‘single row marquee tool’.
6. Click Edit –> Fill and, in the fill dialog box, select pattern
7.Select your custom pattern, and wola! You’ll have a stitched line / dashed line.