which gallery will allow a user to access a variety of preconfigured formatting styles for images that are added to a PowerPoint presentation

Picture Effects gallery.

Explanation:

PowerPoint application can be defined as a software application or program designed and developed by Microsoft, to avail users the ability to create various slides containing textual and multimedia informations that can be used during a presentation. Some of the features available on Microsoft PowerPoint are narrations, transition effects, custom slideshows, animation effects, formatting options etc.

To format an image on PowerPoint, you can either use the Artistic Effects or Picture Effects.

The Picture Effects gallery allows a user to access a variety of preconfigured formatting styles for images that are added to a PowerPoint presentation.

Basically, the Picture Effects consist of the following preconfigured formatting styles; transparent shadow, soft edge, reflection, glow, 3-D rotation, metal frame, bevels, perspectives etc.