[jQuery] Find array key of value

Hi there,

I'm trying to build a custom slideshow (which doesn't loop) but i seem
to be unable to iterate through the array of images correctly.

Content looks like

<div class="images">
    <img src="1.jpg">
    <img src="2.jpg">
    etc....
</div>

I create an array of images as follows

$( ".images img" ).each( function() {
    imgArray.push( $(this).attr( "src" ) );
});

All images except for img:first are hidden, and to change slides i
change img:first's src-attribute with a fade (hope it's clear).
Now i'd like to check img:first's current src-attribute and then
define it's key in the array.

I hope this kind of makes sense. Any help will be greatly appreciated!

Thanks,
Knal