Zoom extents, then export a jpeg. In the jpeg export dialog window, press the "Options" button. Then change the image resolution to something much higher than screeen resolution. SU does not support anything over 9999 pixels I think. And I will often get crashes when try to save anywhere over 8,000 pixels wide or tall if the model is complex. So always save before exporting a high resolution image.
And turn OFF anti-alias. If you leave anti-alias turned on, then SU often struggles with images over 4,000-5,000 pixels.
Chris