Since early August 2015, you get a half-fare card or a general pass only on the so-called Swiss pass, which is provided with a passport-size photo size in the format 35 x 45 mm. In addition to the subscriptions to the SBB the Swiss pass can be used for other services, e.g. for the Mobility CarSharing or for ski passes.
We have compiled the requirements on the photo here, to the SBB’s website and for more information about the Swiss pass, see this link.