Hello, @TFS,
No, it won’t. The size of the media library is not related to individual page load time… However, the number of assets from the media library you use in an individual post and the size of each asset will impact page speed.
Page load times depend, among other things, on how many images you have on your page. Images which are in the library but not on the page should not affect the load time.
Regards 8Themes Team.