I think in some cases (like this thread) it is no problem.
New users have not yet seen those pictures and they are stil of interest.
But for example this thread: https://www.lfs.net/forum/thread/10841
about graphic settings and custom textures. It is from 2006: The graphic engine has changed, computers have changed. After 14 years the download-links are obviously no longer relevant or working. Everything is different.
In such case it is better to make a new thread instead of posting in such old thread. There are so many other, newer threads about graphic settings and textures..why choose a thread from 2006?