String Logic - Add BBCode Into WYSIWYG Rich Text Editor

I've got this code to add bbcode into a wysiwyg rich text editor. Everything's working fine except when I want to add an image. The first time the script is run everything is ok, but the second time I get two image inserts, third time I get three and so on.

Here's the code:
Code:
$('#uploads tr').click(function(){
var filename = $(this).text();
var insert = '[img="'+filename+'"]';
textarea.value = textarea.value+insert;
$('#images').hide();
textarea.focus();
});

So first time I click on '#uploads tr', I get [img="filename"], then if I type some more stuff and then add another image, I get [img="filename"] 'Some more stuff' [img="filename2"][img="filename2"], then I'll get three image tags, then four and so on. I can see that it's something to do with the line I've highlighted, but I can't see why, or how to change it.