Download all gif files

wget -r -l1 --no-parent -A.gif http://www.server.com/dir/

Download pdf files

wget -r -l1 --no-parent -A.pdf http://www.server.com/dir/

Passing headers

wget --header=’Accept: application/xml’ http://bk.host.com/spaces/dyrjBGFKer3kAvabNrdR7q/tickets/1/edit