Unable to send pictures to a certain phone?

My sister inlaw can receive pictures from me or my wife we both have 9900s. She will get our txt msgs but not any pictures. I don't know what phone she has I am pretty is not a smart phone just a basic type. I sent the pic to my son who has an google phone and he forwarded it to her and she got it. I don't think this is my phone issue but am asking here as this has been a good place to find out tech stuff. Sister inlaw is on telus and can send us pics. My wife made her pics smallest to see if size was an issue and that did not work either. Very frustrating trying to figure this out.

Does she have MMS or emails blocked? Does she have them blocked from you both?

well she doesn't think so and its strange because I sent the pic to my son who was able to forward it to her. Seems like there is something the way bb sends the picture that her phone does not like. She gets our texts no problem.