HP 6520 email to 6x4 photo tray and Blackberry 10

Hello

I have just got a HP 6520 and set it up with hpconnected and cloud print.

When I email a photo from my phone, it comes out on A4 paper, not the 6x4 photo paper as expected.  Is this supposed to work?

I have a Blackberry 10 phone and HP are yet to make a consumer version of the ePrint app for it (there is an enterprise version) although im led to believe there is one in the pipeline (there is one for BB7)

I have had limited success with the android version of ePrint.  It does seem to work well enough to print, but crashes quite often, perhaps OS 10.3 will improve this, or HP will release a proper app.

Thanks

Adam