I've done a little testing and a little research on this.
With a little testing, I found that the WipEout Pure browser can display PNG images. It cannot, however, display TIFF images.
Knowing that the 2.0 exploit uses both PNG and TIFF images, I did a little more research as to what the function of the PNG image is. As I don't know assembly or how it works, I couldn't really figure out what it was doing. However, I could figure out that it does execute some code to prepare for the TIFF buffer overflow.
What I'm hoping is that someone more knowledgeable than me can go further and try to do some sort of PNG exploit.
What I'm also hoping is that someone who has Tenchi no Mon or one of the other games with a web browser can test if TIFF images work.
Just use my page that I used to test for TIFF support in the WipEout browser: http://www.vgspot.com/hack/index.html
I see a lot of potential in the WipEout browser. There are some other ideas that I have about it that I'm going to test later on. The best thing about it is that if we find an exploit using a UMD game, Sony can't fix it, because there's obviously no way to update the code on the UMD itself. :)