I would suggest checking out the example of the webcam code on the Anvil of Time website that I posted the previous link to.
The next thing might be to review the EZTwain manual ... http://www.eztwain.com/pub/eztp/EZTwain_User_Guide.pdf&ved=0ahUKEwj4…
I would also look at the EZTwain website information as well around this aspect of the product: EZTwain from PowerBuilder
HTW