The settings in this ButtonsWindow visualise the Texture DataBlock. These buttons are only displayed if:
the active Material has a Texure (see MaterialButtons).
the active Lamp has a Texture (see LampButtons).
the World block has a Texture (see WorldButtons)
Intensity textures: return one value. The previewrender in this window shows this as grey values.
RGB textures: returns three values; they always work on colour.
Bump textures: returns three values; they always work on the normal vector. Only the "Stucci" and "Image" texture can give normals.
The DataButtons in the Header indicate what Texture block is visualised.
If the Texture block has more than one user, this button shows the total. Press the button to make the Texture "Single User". An exact copy is then created.