Frames Mod 1.7.10 adds in iron and wooden frames that you can decorate your world with. These have to be placed on a block but you can remove the block and then they will be free standing.
Screenshots and Usage:
Then you can place the frame on a wall and change it by right-clicking on it:
To change its color, apply a dye with right-click: White dye removes any other dye! To break them you have to use the correct tool i.e. pickaxe for iron, axe for wooden. Or you can break the wooden ones while holding a frame in your hand.
You first have to create beams
How to install Frames Mod 1.7.10
Download Links for Frames Mod 1.7.10
For Minecraft 1.7.2
For Minecraft 1.7.10
For Minecraft 1.8