Thank you Brundle, Perseverence is the name of the game - I clicked only once and decided it wasn't working! All sorted now.
But the annoying thing about this is that right- clicking and changing the 'properties', eg title, obviously amounts to editing because it doesn't work if the file is read only. Yuk.
My sony DSC-T1 shoots only in jpg, so I can't shoot RAW.
Thanks,HS Sutton - you have given me a bit to think about. I do have phases of saving everything to TIFF and then revert to jpgs. I am due to do a full backup on to DVD-DLs so will keep the image files on a master-disk.
I'll mark this thread as resolved. Thanks all.