I am using the fspring theme and it hasn’t been upgraded since at least 2007. Here’s a website using it: https://sentaire.com/ (my site is NSFW)
I just belatedly noticed under Display Options when I try to click on the Thumbnails button it is grayed out and unavailable to use as an option. The mouse-over reads: This option is disabled because your theme does not support post thumbnails.
I’m not sure if that is referring to the actual blog posts, or indicating thumbnails can not be generated below the blog post. I use pictures in every post so I assume it is referring to after the post.
Appreciate your help…