can I pass user defined types as arguments?

my first question is can you include image handles in
your type

type bullet
field x,y
field whatever
field bulletimage ?????
end type

my second is can you pass a type as an argument to a function
For bullet.bullet = each bullet
if blah blah blah
DoSomething(bullet)
elseif
blah blah blah
else
blah blah blah
end if
Next
end function