Just about any 3meg - 3X zoom camera will work for email.
But the need for a lithium battery just about leaves out any 3-by-3 low cost cameras.
A good flash is not common with digital cameras.
I came up with one that seems to fit the profile.
It is 5meg and 3X zoom.
The Nikon 5900
A review can be found here:
I looking for a Camera to take pics of homes to send over the net lowest setting jpeg like to have one that has a info lithum batterie and take a beating and a good flash it will be for work megs dont mater any help would be nice