fade problem on .hover

fade problem on .hover

hello together,
I am really desperate.
since yesterday night I am trying to figure out why my script is not doing what I want it to do (that could be the reason that I am very new to jquery)

I wrote a little script, which fadein my pictures here


$(document).ready(function(){
               
$('#bild-gross').fadeIn(2000);
$('#bilder-klein').fadeTo('fast',0.6);
$('#bilder-klein').slideDown(500);
};


strange thing is:
when I upload my script with these lines in it:

$("#bilder-klein img").hover(function(){
   $(this).fadeTo('fast',0.2);
   $(this).fadeTo('slow',1);


nothing happen at all!
can someone help me out here?

the last code should effect only my thumbnails.
I am really stuck here and just can't solve my problem.