I added a photo from arcgisonline to a map that we are using for engineering at an irrigation dam site. It turned out that the image at World_Imagery captures a very illuminating high water event at the site. It is a different image than at ESRI_Imagery_World_2D or Google Earth. I have records at river flows for each day. If I could date the photo, I could say what flow the river was at when the photo was taken.