Next time re-read your comment for errors before you post
Mmmmm... there would have too been many bloodstains on a uniform taken from the dead.
As for women in the IG, besides Lieutenant Mira Nero, there's all the women in Gaunt's Ghosts and Ciaphas Cain novels who typically occupy some middle-tier post in the chain of Imperial command. I can't remember any of their names unfortunately... General Sulla, I remember her, she is freaking awesome.
The comedy in this picture comes from how bad the uniform fits the farseer. If it wasn't so ridiculous it wouldn't be funny.
Here is a chain of thought:
farseers live in craftworlds.
craftworlds are fully functioning societies where everyone sees to everyone else's needs.
therefore there would be tailors and crafters who could create an imperial guard uniform as a disguise for a farseer.