Flood fill tool - Fill the pixels that you click, and neighboring pixels of similar color, with the Flood fill color and Opacity set below.
Flood fill color - You can choose Transparent or pick any color on your screen using the color picker.
Flood fill Tolerance - Neighboring pixels are only filled if their values fall within this range. So it can be used as a magic wand.
By choosing Transparent, you can set the image transparent:
Brush tool - For painting brush strokes on the image. It uses the width, color, and opacity set below.
Brush Color - You can click and pick any color on your screen using the color picker.
Brush width - Pick from the drop down.
Opacity - The Flood fill and Brush Opacity
(5%: Mostly transparent - 100%: Complete opaque)
Opacity operation example:
Opacity works for both Flood fill and Brush.
More on image processing features
Copy & paste operations
Next: Transparency >