I’d like to know if I can put a title under eac...

Yes, you can add a title and a description with ALT & TITLE attributes. title=”This is a description” alt=”This is a title”

Code:

<a data-gal="prettyPhoto[gallery]" href="imagepath.jpg" title="This is the description"><img src="images/playgal.png" class="left galleryicon" alt="This is the title" /> Gallery</a>