737 Fuel Pump Photo
 

http://www.jetphotos.net/viewphoto.php?id=5793015

Has this guy got the ctr tank pumps on with a dry tank? It looks that way to me.

Wow Very observant, you must have really studied this pic!

The fuel indicators on 737 are pretty inacurate, so when you have zero in the centre you may still have some fuel for up to a couple of minutes.

Master caution hasn't come on either. Easy to miss.

If you look closely enough, which you evidently must have, neither centre tank low pressure light is lit meaning there is still fuel in the tank and both pumps are working.

The centre tank gauge, especially on the 3/4/500, can often read zero when there is still fuel in there and as such the master caution won't come on until BOTH low pressure lights are lit. This is really the only way to tell that the tank is actually empty.

I don't know whether to say 10/10 for observation or you need to get out a bit more! :;)

Centre tank pump switches
 

Your right about the low pressure lights, both on to get the master caution.But if one comes on first as it usually does, (standpipes) you'ill get the master caution on pressing "recall"
However if for some reason you select one centre tank pump switch on (mel perhaps) and there is fuel,(low pressure light out) You will get the master caution and fuel light on pressing "recall". This is the only time,that i can think of, you'ill get something on the master caution and not have an amber light illuminated on the overhead.
This was the case on the 2,3,4,500.anyway.
Try it next time you've fuel in the centre. Usual caveats about use of centre tank pumps.