Actually the facility that takes them owns the film / data generally...
You can, for no cost, pick them up there and bring them to the new Dr. to view, and then return them.
Or for a few $, they will make a copy that you can keep.
Been here, and I just checked them out for a week...
That all the new Dr. wants anyway is to see them when you go in for your appt...
A radiologist has already looked at them and made notes as to what she/he thinks. You should get a copy of those notes as well...