4.Paint bucket tool
It is used for filling some parts choosen form you.
After you have choosed the tool in the menu you can choose FIll.
Foreground-fills the color you have choosed
Pattern- makes Pattern
From the mode menu you can choose the way of the mixing
From the Opacity menu you choos the transperance.
From the Tolerance menu you choose the tolerance of the colors of the near-by pixels in the one you click with the tool.
Anti-aliased clears the conturs
Contigous if this is on after you click with the tool only the pixels that are next to each other and have similar colors will be colored.
And if this option is off the pixels with the same colors will be colored not only wher you have clicked but everywhere in the image.



