How to copy some files/images to a client's computer?

Is there any way to copy images from server to client´s computer automaticly without the user to notice it?

There is, but it is against the law in every country, and is severely punished.

Thank Goodness NO

Because if you could do it withoug the user noticing it, other people could do it without users noticing it.  And the hackers are good enough about this without any help.

Now, with an air application you may be able to do something behind the scenes with the users permission, but I don't know about that.