So I have an application that does:
Take n amount of links from SQL
Creates a new thread for each link
Get HTML code of this website with HTML-Agility-Pack for each thread
Saves its data to SQL (image sizes, page size, word count, words etc) and saves this process with its date
This is to check the data on a website and see if there is any changes (like a typo or a problem with images that were previously uploaded) and I want to add a screenshot/thumbnail to these for each page. How can I take a screenshot of the whole page during each thread?
Seems like an interesting app. As you already get the HTML for the entire URL (I would assume the app is running on a machine/server which has internet connectivity):
There are 3 ways you can do this (many more actually).