Originally Posted by zinfinion
One caveat you might want to add to the OP is that Steam screenshots will not show the injected FXAA/SMAA. Something about the AA being an overlay and not directly in the framebuffer or some mumbo jumbo of that sort. Best to use the screenshot option built into the injector.
It's not a bug .. it's a feature
The screenshot function in most games and overlays will capture the screen before it was modified by a shadermod.
This can actually be useful if you want to capture both a before and an after shot of the screen.
The best way I've found to do this is to make sure both the screenshot function in the game/overlay and in the shader mod are mapped to the same key.
That way when you press it, you take two screenshots of nearly the same frame, even if the game has no pause function - which is great for comparisons.
If it does have a pause function then I suggest pausing so you are sure to capture the exact same frame.