SQL Server :: Insert Date And No Duplicates

I am importing images names from a file into a database by using the code below. When I import the image names, I aslo want to add a date of "June 12, 2009" in the DATE column. Finally, I do not want to import any duplicates. Is there something I can change in this code to make that happen?

declare @cmd varchar(1000)
set @cmd = 'dir "D:imagesREVIVE" /b'
if (object_id('ImageTable..tblimages') is not null)
begin
insert into tblimages (imgname)
execute xp_cmdshell @cmd
delete e
from tblimages e
where ISNULL(e.imgname, '') = ''
select *
from tblimages
end
else
create table tblimages ([id] int identity(1,1), imgname varchar(1000))
insert into tblimages (imgname)
execute xp_cmdshell @cmd
delete e
from tblimages e
where ISNULL(e.imgname, '') = ''
select *
from tblimages