Ok........Idiot
Firstly let me reassure you that you won't mess up your phone, all you're doing is overwriting a pink image with a blue image
Tools you need:
Resco Explorer or
Total Commander
you can either unzip the file on your desktop, or send the zip to the phone and unzip it on the phone using the built in zip utility (found in the Start menu), this will probably depend on how you want to send the files. If you email them then leave them zipped and unzip them on the phone. If you connect the phone to your PC using ActiveSync ( or WMDC if you have Vista) then unzip the file on the desktop and copy the individual files over
Either way get the images into a folder in, for example, My Documents
Now using Resco Explorer or Total Commander (that you already installed

) browse to the files and copy them into \Windows, as I said in my post above you will probably get a warning saying they are system files, are you sure blah blah. To which of course you say yes because they are just pictures!!!
now go to Start>Settings>Today>Items and remove the HTC Home plugin, reload it again and it should be all blue

If not then a soft reset will sort it
Mine's a Carlsberg
