Photos in the Gallery can be added or edited using “Add Media” above.
Click “Upload Files” to add new images. You do NOT have to click the “Insert into Page” button. Just close the “Add Media” window once you have finished uploading.
To remove images or change the order, click “Media Library” and then select “Uploaded to this page” from the “Filter Media” drop-down. You can drag images into a new order, and to remove one, select it, and then click the little red “Delete permanently” link at right.