show different content on individual post page?

Hey everyone.. so now im trying to figure out if theres some kind of plugin maybe, so on my home page, the blog page. or on the category pages that list the posts, when you click on the header link that brings you to the page dedicated to that post, it displays the exact same content, on my site i dont use excerpts, on my home blog page, and on my category pages, i have the posts displaying fully, i use wp as CMS. now when someone click on the head link to the posts page, i would like to remove some thumbnails and then enlarge the smaller sized video… hope this makes sense?
anyone know of a way to do this ?

its like on the blog page and cat pages i want A and B to display, fully, but on the posts page, i just want to remove B, keep a, but make A have a larger height and width…. make sense?
thanks!!