Look for colors of her clothes. Yes, she could be intact still if in the water. If she was not weighted down, there is a better chance she would be intact. Decomp varies depending on the conditions.
Also note areas of earth which look recently disturbed in the fields and yards. This will be very small (probably too small to see on these), but if it appears out of place...they can magnify it to sort out the details.
I look overall for things which appear out of place in the photo first. Then I use a grid method starting in one corner and working through the photo a tiny bit at a time. If something catches my eye, I look for similar objects and usually find there is more than one so I can rule it out.
I try to find a reference point to compare size in each photo, too. (This isn't easy from the air.)
Look for 55 gallon drums, containers, or suitcases.