It means to ride on a persons back or be carried on someone's back as if you were strapped to it, but in this case it means...camera technology was made popular by mobile phones, as if the only way camera technology became popular is because " it has rode in on the backs of mobile phones" it's not a literal meaning. This suggest cam technology wasn't popular before it was presented to us as a feature of mobile phones

to piggyback is literally to ride on the back of someone or something. Here, it's used metaphorically, to say that embedded camera technology became popular because mobile phones became popular and the cameras were embedded in the phones. Cameras were, figuratively speaking, riding on the phones, and as more and more people got phones, they got cameras as well.