docs/31109: replace gif images w/ png ones due to patent license

[Joseph Scott]

On Jul 25, 2004, at 7:16 PM, Tom Rhodes wrote:

> On Sat, 24 Jul 2004 21:59:11 -0700
> Joseph Scott <joseph at randomnetworks.com> wrote:
>
>> 	Given that the GIF patent has expired does this PR still need to be
>> open?
>
> Depends, are there any other or pending patents?

	I don't know, but I figured that if it was good enough for gd to bring 
back gif support things were ok.

--
Joseph Scott
http://joseph.randomnetworks.com/