Lightroom Library

In the Grid view, do any of the following to rearrange photos in the grid:
1. Click the Sort Direction icon in the toolbar.

2. Choose a sort option from the Sort pop-up menu in the toolbar to sort photos by Capture Time, Checked State, File Name, or Media Type.
3. Drag from the center of a thumbnail to sort in any order.

You cannot drag to rearrange the order of photos in Grid view when they are in a folder that contains a subfolder of more photos.