Greg, thanks! I couldn't get the Auto Arrange to change from gray to black. Then I realized you had your pictures displayed as thumbnails. (I didn't even realize I could do that!) As soon as I changed to thumbnails, I was able to rearrange their order. Thanks a million for your patience.
I'm glad it worked out. If you turn Auto Arrange back on, you should be able to just drag the pictures in the order you want and still look neat and tidy. I forgot to mention to do that, thumbnail view needed to be enabled.