Maps can be
saved as bitmaps
or as
windows metafiles.
Saving:
Clicking the save button brings up the usual dialogue box:

Use the Save box's drop-down 'filter' to select
the type of graphic file you want to produce.
Bitmaps:
The bitmap file (filename.bmp) looks exactly like the map displayed by
Stargaze itself:

Sample from a map saved as a bitmap.
The size of the saved map - which can be adjusted using the enlarge/reduce buttons - is given in Stargaze’s status bar.
Bitmaps take up a lot of memory, cannot be edited easily and will not look well
if scaled up or down after saving.
Windows metafiles:
A star map saved
as a Metafile (filename.wmf) takes up a lot less memory, still looks good when
resized and, if you have suitable software, can easily be edited.

The same detail as above but
from a map saved as a metafile.