When to have a title

First of all, you don't need to have a title. So, only have one if you need it. Sometimes, an image on its own, is an interesting enough way for a visitor to simply start exploring, and discover your stories for themselves. 

A title can be used to simply flag name of the object, image or document. 

You could also add a logo or exhibition title, if that's what is needed. 

Keep it short, this is not the place to say anymore other than the main heading.