Featured Image as Header Image

Hello, can anyone point me to any tutorials or share some code that would set the latest blog post featured image as the front page header image when visitors first load the site. Then for the single page, is it possible to have that pages featured image as the header.

What i’m wanting to achieve is visitors are greated with a large full res photo, scroll down and see a masonry like grid of latest posts, square and rectangular with links to the single post’s page.

When viewing the single posts page, the featured image for that particular post is the header image that scrolls away as they scroll to the content.

If anyone can point me in the right direction, thanks!