I have certain coworkers with ralph wiggum as their contact photo in my work phone.
Why did you put their photos as Ralph Wiggum?
I think it is funny to do it.
That seems like an innocent joke. It is good to do things that you find funny as long as it doesn't offend others.
They also think it is funny.
It is good you and your coworkers can bond over this. Lighthearted fun can keep your relationships close.