some questions about shiny,such as html and picture

[WMJ]

Hello,everybody
I'm studying shiny,but I meet some questions.

1. HTML
   I want to build my entire UI with HTML, I also study the example(Shiny - Build your entire UI with HTML),but I meet a question.
   I want to select labels to be automatically generated based on my files. But I failed.Could someone solve this problem?
2. shiny-Picture parameter
   For the above reasons, I re-use ui.r.Unfortunately, I have encountered another problem.
   
   
   
   My graph is generated according to the selection,but the size of the image needs to be determined from the beginning. Your know,this will make the picture very ugly because it is too crowded or space.

So,Could someone help me ?