I'm playing the game on a 2008 iMac with a default screen resolution of 1680 x 1050 pixels. However, in an attempt to improve game performance I've lowered my in-game display resolution to 1562 x 976 (though it hasn't really helped). This has created a problem with my screenshots.
Basically, although my in-game resolution is set to 1562 x 976, the actual display is still utilizing my screen's full 1680 x 1050 pixels (as expected), meaning that the "virtual" pixels are being "stretched" to fill the entire physical screen. This is normal, and expected. I realize it's an approximation, because unlike old CRT screens, modern LCD screens are designed to work at one specific resolution.
My problem is with how WoW's built-in screenshot function is handling it. Instead of capturing the stretched "virtual" 1562 x 976 pixels (that is, the entire screen), it's only capturing "real, physical" 1562 x 976 pixels. Put in simpler terms, the screenshot function is counting physical 1562 x 976, instead of simply capturing the entire screen.
Here's what I see onscreen in-game, captured using Mac OS X's own screenshot function (Command+Shift+3):
And here's what I get using WoW's own screenshot function:
As you can see, the in-game screenshot function has cropped off the top and right sides of the image. This isn't a big issue if I'm just taking a screenshot for a pretty picture. But a lot of my screenshots are taken for the purpose of reporting bugs or other issues, and in those cases it's often necessary to know the specific location, and that information is displayed in the areas that are getting chopped off.