1. Create a new file with size 5x5 or 10x10.. in this tutorial, I'll go with 5x5
2. ZOOMMMMMMMMMMMM~!!!!!!!
3.Make a new layer and delete the Background Layer, we don't want a pattern with white background on it don't we?
Yep, delete that Background layer..
4.Now.. carefully, use brush and do a diagonal line... if there's too much on it, you can delete it... remember, use 1px eraser/brush for this one~
This is what is should be looks like now..
5. Go to "Edit" on the top menu bar... then there should be something called "Define Pattern"
This window will pops up...
6. Name your pattern and then click OK!
7. Then, go to the picture that you want to add diagonal line, and go to blending option
Right click the layer... then this'll pop out.. again...
8. then, go to Pattern Overlay, and search for the Pattern that you just created before..
You could even play around with the Blending Option xD welp, I'll set mine to vivid light~ with 100% Oppacity and 101 Scale (Remember Scale = Size of the Pattern)
9. Aaaand we're done~!