measuring arms

[prodigy06]

So, when I measure my arms I measure flexed from the peak of the bicep to the lowest part of where my tricep dips down so I get the tape around ALL of my arm. But this isn't a straight line like how I see sme guys do it, it's sort of slanted. Am I dong it right?
Here's a pic of how I do it (RED) and how I've seen some others do it (GREEN)... the green line is supposed t be striaghter...
We're all dif, so I assume whatever gets you the largest measurment is the way you should do it, right?

How do you do it?
EDIT: No that's not my arm.. I know someone will ask, no it's not.

[Grizzly]

Dude, you have to measure straight. By curving it, you're inflating your measurement.

Just measure around the widest part. WRT the picture, the angle of his arm is what throws you off. It would, indeed, be straight line from peak to belly.

[FiberSynk]

If that was your arm, and you still didnt know how to measure........well ive seen worse