Microsoft PowerPoint has a wonderful feature for equalizing the spacing out. It is called Distribute Horizontally or Distribute Vertically. What it does, is even out the spacing between the inner objects leaving the outer objects in place.
For example, if I have 2 objects that are outside edges 12 inches apart, and the objects are 1" wide each, that leaves 10" between them. Now, if I add a 3rd object randomly in between them, it now places the 3 objects evenly spaced apart with 4.5" in between each item. If i add a 4th randomly placed object between the items, then the outside objects still stay in place, and the 2 inside objects now are spaced equally between them with 2.67" between them every item.
This would be extremely useful to speed up the process when adding several images on a page, with equal spacing between them. Let's say I have 4 pictures wide by 4 pictures tall, and decide I want to add 1 more column of images. all I would have to do it select the 5 images wide and click the distribute horizontally button, and it equalizes the spacing between the outer most objects selected. Then do the same for the remaining rows. I could also then select the columns to distribute the objects equally as well.
This would be the same as having a table with 4 columns and 4 rows, with the images centered vertically and horizontally, then adding an additional column to the table, they all automatically re-align to have the same spacing between them.