I have written the script file now and I am including a zip below. To use this script you will need to put the contents of the zip in a fresh directory and ensure that you have a version of ImageMagick installed.
To run it, put an image to be tiled into that directory and call it start.png. Open up a command prompt and navigate to the directory. Type :-
The first parameter is how much flattening you want. 0 is none, 1 is low, 2 is medium, 3 is high.Code:GenTiled.bat 1 start.png
It should run for a while printing out a little status message now and again until it quits. You should get the image Final.png and Array.png which is a 3x3 tiled array of them to look at and see how well itd done it.
You can change the starting image filename to whatever you want and it can be of any size and aspect but the Final.png will always be of size 1024x1024 and of PNG type unless you modify the script.
It takes a little too long to run as a CGI script. I dont think my ISP would approve of the processing power consumed. If any of you are running a private web server then you could convert to a CGI script which would make an easy interface for the conversion.
Bugs and comments welcome as usual.