Use this field to specify meta-information required by the explicit image formats: gradient, plasma, label, and caption. For gradient or plasma specify a color range such as blue-yellow. You can also specify fractal for the plasma image format. For label specify any text to render as a label. The caption format is similar except you can enter a paragraph rather than a single line of text. Finally, for hald specify the number of levels, typically 8.

Choose a format of xc, set the canvas size, and set this field to the canvas color. Choose none to create a transparent image.