If you want to hide text, you can use [
color] [/
color] of the post's background. Then add a note that it's a spoiler and if you want to view it, select the hidden text.
To make it easier for you, here are some colors:
| Post background 1 | [color=#173C56]TEST[/color] |
| Post background 2 | [color=#1B4665]TEST[/color] |
| Quote background | [color=#567E9A]TEST[/color] |
If you want to hide images... just use links instead.