01 - Open A New Image, 1px Wide, 3px Tall, Transparent Background
02 - Zoom In To 1600%
03 - Select The Paintbrush And Make A 1px By 1px Brush
03 - Make The Top Pixel Of Your Image The Color You Want The Scanlines
04 - Edit > Define Pattern, Name It Anything You Want, Ill Call It "DJs Scanlines"
05 - Open The Image You Want Your Scanlines On
06 - Create A New Layer
07 - Select The Paint Bucket Tool And Change The Mode To A Pattern
08 - Fill The Layer With Your Scanline (DJs Scanlines)
09 - Edit The Layer Transperancy To Your Liking, Maybe Even Adjust The Layer Blending Options
10 - Your Done!
By DJ_Durst