I just chanced upon this site which sells vintage postcards. They classify them both by subject matter and by country; there are just a few from Bahrain, but plenty from other countries in the region (I haven’t looked outside the Middle East yet). Some of the titles are as interesting as the images themselves, telling you a lot about who was taking the photos and what they chose to see.

‘Persian tailor smoking a qalyan’ - which I assume is the same as shisha.