drupal 7 views horizontal align not working in grid?
You can horizontally align things with CSS

e.g

.container{
  text-align:center;
}


You can also align using a margin or padding.

In your case:

.view-galleryofimages .views-view-grid {
  margin:0 auto;
}


Should suffice.

See this summary for more info: CSS Horizontal Align