Are social phobia cases on rise, being the Internet and mobile phones with cameras the main cause for their rise?
Studies have been done to see how technology can alleviate social phobia, by communication through the net. (Yen et al 2012)

Heavy use increases (general) anxiety: (Anxiety was measured using the Beck Anxiety Inventory.) "Logistic regression analyses indicated that heavy Internet use is associated with high anxiety; high cell-phone use is associated to being female, and having high anxiety and insomnia." (Jenaro et al, 2006) *2 A replication of this study with a comparable population might answer your question.

Other studies have shown that "social phobia was associated with the risk for smartphone addiction in young people." (Darcin et al, 2016)

A study published 2009 sets the prevalence rates of social phobia at "in community samples of children and adolescents also vary considerably, ranging from 0.9 to 13.1% [26]. The highest rates have been noted in studies of older adolescents and young adults ", and sets the numbers for the whole population, quoting other articles,  "3.9–13.7% in Western societies" (Gren-Landell et al). 

The prevalence numbers seem to vary wildly depending on how the research has been done, as Furmark (2002) points out in his review of epidemiological studies from the 1980s onwards. - Doing this with current research would give more of an insight into your question.

So I'm sorry to say I couldn't, so far, find a study that specifically addresses your issue. :-(