1. Open Photoshop. Open an image to apply angled lines effect.
2. Create New file with 3 pixel width, 3 pixel height and transparent background.
3. Select some foreground color. Draw angled line using Pencil Tool.
4. Select All using CTRL + A
5. Create a pattern by Edit > Define Pattern. Name the pattern.
6. Close the Pattern file and go back to image file. Create new layer. Keep it selected.