There doesn't appear to be a genealogy or historical society in Elmore County or a Random Acts Genealogical Kindness volunteer. Your next best bet for a picture of his tombstone is to post that request on www.findagrave.com
. It might take awhile for someone to take it. The name of the cemetery is Glenn Rest.
You can request a copy of his obituary from Random Acts Genealogical Kindness. Go to www.raogk.org
, read guidelines, choose Idaho, Choose All. There is a volunteer (John) who does obituary lookups for the entire state. Be sure to tell him that Frank died in Boise but was buried in Glenns Ferry, Elmore Co. Successful Searching!