This means that everyone is welcome to come and taste these delicacies.

The male teacher posted a picture of the dishes on the table to celebrate the meal. If you want something to eat, please come.

This sentence means that the male teacher showed off the dishes on the table during the celebration meal and invited everyone to enjoy it.

He said "come if you want to eat" to express that everyone is welcome to come and taste these delicacies.

The "show" in this sentence refers to showing it through photos or words. "Celebrate eating" may mean that he has some happy events or special occasions, so he prepared some delicious dishes to celebrate. "Have something to eat"

" means that he has prepared food, and "Come here" is a friendly invitation.