[jQuery] callback function

[mlabee01]

Hello,

I’m pretty new in the jQuery world. I'm struggle with the callback
function.
 <script type="text/javascript">
        $(document).ready(function(){
                $("#gallery-flickr").flickr({api_key:
"f28804be7a09c5845676349c7e47d636",per_page: 4 });
                $('a').attr({  rel: "prettyPhoto"});
        });
</script>

In the first line 4 photos are retrieved from flickr. In the second
line rel: "prettyPhoto" has been added to the 4 received photo lines
from flickr. This action must perform after all the photo info has
been received.

It is my understanding that this can be done via the callback
function. Albeit I understand the idea behind the callback I do not
understand the syntax. What I really want is that the action =>$
('a').attr({  rel: "prettyPhoto"});<= has been performed when the
first action
=> $("#gallery-flickr").flickr({api_key:
"f28804be7a09c5845676349c7e47d636",per_page: 4 });<=
has been finished.

Any help will appreciated
Marinus