Shoutbox

Even if there's such scripts, your contacts can definitely go to the particular folder which contants saved display pictures and use it for their ownselves.
When you show your display picture, that'lll mean your current display picture will be downloaded automatically onto your contacts' PC as a cache so that they can view it!
Just like when you view a particular HTML web page, images are downloaded onto your PC in your temporary internet folder, so that in the future when you view that page, it will load faster. It's the same as the display pictures on messenger.
And thus, it's useless for one to develop such scripts. Seriously.

I know... 

I just want a script that blocks that script. 

~Budsie

It's now been said about 6 times that it's not possible! Give in already!

Scripts on your computer can communicate with scripts on your contacts' computers - but that's at your contacts' scripts' discretion. You can't force a script that works entirely within their computer to stop working, just the same as you can't control their browser - their DP stealer script neither requires nor uses any input from you, and hence you can't stop it.