Where you got your information from, I don't know, but when I convert png's to gif the filesize increases.

I get it from the programmes I use. Photoshop and Photo Editor.

At the same time I just made a PNG with Photoshop and saved it at 6.82KB and then coverted to GIF which saved at 2.97KB. I then saved the GIF back as a PNG and it saved at 5.32KB. There's every chance it would depend on what settings you use in whatever image editing programme you use whether it be Photoshop or something else.

I'm not saying you are completely wrong here, what I am saying is that it will be many years before webmasters shake off GIF images. If you go to any corporate website the chances of finding JPG and GIF there are very good. For the record I didn't follow the links provided because it's obvious that you wouldn't provide anything contrary to what you mentioned but what Yale University (where-ever that is) finds as a result of some experiment is clearly not being used in practice.

In light of this, I visited my own sites plus the two you own and there are GIF files a-plenty and 0% PNGs that I happened to have seen. Our choice of format simply happens to be reflected on a massive scale all around the world. PNG will one day takeover but it will probably take as much time as DVD did to claim Numero Uno spot from tape.