1.You need to edit the size of the picture and the size is usually displayed there. Where those options are depends on your Software.
2. A frame is a border around the thumbnail. I just add 2 because it looks better.
This post will help you further: https://steemit.com/dtube/@valorforfreedom/3xnnkuzm
And don't worry about it, we are all newbies when we learn something new.
Thank you !! I look forward to your up coming articles :-)