Export Preferences
Export with room around the graphics - By default, there is a bit of extra padding around graphics that are exported. If you want to control the exact size of the exported image, turn off this setting.
For example, to export an image that is exactly 300x400 pixels, turn off Export with room around the graphics. Then create a shape and use the Position pane to set its size to 300x400. Use the Style pane to turn off the stroke, fill and shadow. Use Send To Back and Lock the shape in place so it will not get in your way while editing other graphics. As long as the graphics are within the bounds of the background shape, your exported image will be 300x400.

Export Bitmaps at a resolution of - Use this setting if you want to export TIFF, JPEG, GIF, or PNG images at a higher resolution than what is displayed on the screen.

JPEG compression - The JPEG image format allows a variable compression ratio. More compression results in a visible loss of image quality but a smaller file size, and less compression results in a crisper image but a larger file. The setting on this slider will be used whenever exporting images in JPEG format.

HTML image type - The image format chosen here will be used for images exported with the HTML Image Map option.
Related Topics
OmniGraffle Preferences
Table of Contents: Customizing OmniGraffle
Table of Contents: Reference
Main Table of Contents