The AutoDistribute option produces an even grid of all the images on your canvas.

Add your images to the canvas, via Autocollage or by dropping them individually through the Images hover.
Choose 'AutoDistribute' from the Tools menu to create a grid.

To SORT your images before AutoDistributing...

Hover on the AutoCollage button, and select the sort features you would like to use:

When you click on AutoDistribute, the sort criteria will be applied to assign the images into frames