In your Image Manager, click on the name of the shoot or gallery on the left side menu.
Removing an Asset from a Gallery or Shoot
Select the asset or assets you want to remove, right click, and select "Remove from gallery/shoot."
Renaming a Gallery or Shoot
At the top area (above the thumbnails), click on the name of the gallery or shoot to edit it.
Deleting a Gallery or Shoot
You can delete a gallery or shoot from the "Actions" menu in the top right corner.