Files can be imported in 
.xyz and 
.xml native format, 
selected automatically by the file extension. Files can be exported 
in 
.ps, 
.ppm, 
.jp[e]g, 
.png, 
.tif[f],
.x3d and native 
.xml formats, selected automatically by 
the file extension. Formats 
.jp[e]g, 
.png and 
.tif[f]
require 
pnmtojpeg, 
pnmtopng, 
pnmtotiff, widely 
available and usually installed by default in most systems.
Files can be exported using 
File->Export. Only the object and 
config data regarding the currently selected object is actually exported!
To  select  an object, choose 
Object->Select and press over the object.
Or choose the object class on the menu above, with the  middle  button, before 
pressing on the object. Or press twice 
Layer, 
Window or 
Gamgi
on the menu above. When the object has no visual representation, press the
mouse over the graphic area, to pop up a menu. The statusbar shows the 
selected object (left) and layer (right).
Files can be imported using 
File->Import or adding 
filenames to the command line, when starting Gamgi:
gamgi file_1.xml ... file_n.xml
where file_n.xml is a fullname such as:
../dat/molecule/flavors/garlic.xml
~/gamgi/dat/molecule/flavors/garlic.xml
http://www.gamgi.org/dat/molecule/flavors/garlic.xml
ftp://ftp.gamgi.org/gamgi/dat/molecule/flavors/garlic.xml
Object  and  config data can be mixed, so file_1.xml might be a preferences 
file, loaded before the other object files. To automate the  procedure, just 
add a line as this to .bashrc:
alias gamgi='gamgi ~/gamgi/my_defaults.xml'
Detailed explanations of valid formats, are available at
http://www.gamgi.org/formats/formats.html, 
doc/formats/formats.html
or 
Help->Topic->Formats.