To export the current file to an image, use
-> .Available formats are VRML, PDF, Postscript, Encapsulated Postscript, and the formats with write support in GdkPixbuf.
To choose a format, you can use an appropriate extension in the file name, or explicitly select a format in the combo box. With the first method, if Gnome Crystal does not recognize an extension, the exported file will be a VRML file. Gnome Crystal will add an extension to the file name if needed.