Creating a banner? Read this
Final resolution: 1920x600 pixels.
Do not STRETCH the picture. You can properly resize/scale pictures usually by holding SHIFT while draggin the corner.
Keep in mind that the lower-left of your banner will be covered by Profile Picture/Avatar
How to set PS4 banner
Open bramantya.org/ps4b on PS4 web browser (press SQUARE to go Fullscreen).
Open the image you want to use as a cover.
Move your cursor to the black area.
Screenshot it with SHARE button.
Open your profile menu.
Click [...] button.
Click [Change Cover Image].
Now follow the on-screen instructions.