使用html agility pack从c＃中的html中提取图像URL，并将它们写入xml文件中

I am new to c# and I really need help with the following problem. I wish to extract the photos urls from a webpage that have a specific pattern. For example I wish to extract all the images that have the following pattern name_412s.jpg. I use the following code to extract images from html, but I do not kow how to adapt it.I am new to c# and I really need help with the