Hello.

I am looking for a site that has advanced drawing tools, like flood fill, maybe upload picture then edit it...

Most have:
Multiple users draw/edit at same time.

Reasonable picture size (1k pixels x and y size)

Has tools like, sizes of pencil, color pallet, and possibly layers.

And oh, does any of the drawing support undo? .... i found 0 so far.

If anybody know of a such good site, please let me know!

Something like Piskel?

Missed the requirement for multiple users at once, I don't think Piskel has that, sorry...

http://flockdraw.com/ seems similar to what you're looking for. The tools seem a little limited, but it has fill and pencil size and such. I don't see an 'undo' option, but it looks like they have community tools and mods, so perhaps mods can still fill whatever needs you have.

http://www.onemotion.com/flash/sketch-paint/ and http://www.ratemydrawings.com/index.php look like they have slightly more advance tools, but perhaps still not as advanced as you're looking for.

I'm not certain the details of your situation, but could you set up some sort of remote access and just host photoshop or whatever you would prefer to use on your own computer? If you're in need of an advanced drawing program, it might be the best option, I think (I have no idea if that breaks any sort of copyright rules. I don't mean to be promoting illegal activities :P If it does, I suggest GIMP).

This site is pretty cool

http://www161.lunapic.com/editor/

This site is pretty cool

http://www161.lunapic.com/editor/

If it would only support multy user editing, that would be perfect.

Currently i found 0 sites that support such a feet, and 0 programs.