1) Use jump.cgi: <%config.db_cgi_url%>/jump.cgi?ID=<%ID%>;view=FileColumnName (or use download=FileColumnName instead of view=... if you want it to be downloaded instead of viewed inline).
2) Write your own global like it has been done in this thread (note that your image directory has to be web accessible for this to work). With the spaces problem (it's actually any non 0-9a-z_.- character), it should have been fixed in Links SQL 2.1.0.
Adrian