The Export Image dialog appears before you select the location where you will save an image of your diagram. On this dialog, you specify the quality of the image being saved. By default, the resolution is set to 72 DPI, which is suitable for reading on most computer screens. If you plan on printing your diagram, you may want to enter a value between 240 and 300 for best results. A higher resolution will result in a larger image file.The effect of not using a background color depends on the output format. For image format that support transparency, for example PNG format, the background will become transparent while no background color is used. Otherwise the white background will be used.
Resolution Output image resolution (DPI).
Margin Space on the edge of the image in pixels.
Transparent Click to set the background to transparent.
Color Click to select the color to be used as the background color.