Or, you can select Minimize Colour Table from the Colours menu. Found in the Picture menu under Colours, produces a dialog box which sets the options for changing the colour depth. You can use the system colour table or the optimized colour table. Transparent GIF Colour. Found in the Picture menu under Colours, this produces a dialog to set the transparent GIF colour.
All available colours are at the left.
You select the transparent colour by clicking in the colour box. On the right side is a preview. You will see the desktop pattern through the transparent parts of the image. From the Picture menu, this flips the picture either horizontally or vertically. From the Effect menu, displays a dialog with the intensity histogram of the picture.