I've seen some pretty good pro-yuri banners in the past, ones that were intended to be sily. My favorite one was a screen shot from some anime where one girl had tackled another one, and just below this picture was a caption that read: "What happens when girls wear Axe".

I thought it was classic.

I just came across this image (the name of the anime escapes me) that supports Yuri over Yaoi.
Yuri

I know it's kinda hard to read but the caption says: "Yuri. Invented just to steal yaoi's thunder"
Now depending on how you feel about that it's either funny or demeaning.

I chose to laugh when I read it myself.

Didn't know if anyone else had any fun captioned pics to share also.