>>4262733>lazy>doesn't contribute anything of value>bumps what could be a dead thread to page 1Different reasons. Threads on /c/ exist for images, not discussion or anything else (that stuff can and does still happen, but it's common courtesy to attach an image). It takes zero effort to attach an image with your post so may as well do it since that's the main reason why everyone is here.
All threads exist to provide content, and to keep a thread alive without providing the board with some kind of content makes no sense. It also helps separate us from /a/ where board quality isn't important to the board users.
If you don't have anything on have to contribute or have run out of images, you can still use sage when posting as that is still a thing on /c/.