If you are planning or using jQuery JS library in SharePoint 2010, there is one thing you didn't plan - for sure.
The $ sign from jQuery library is conflicted with the $ sign used in SharePoint JS - only in picture library "thumbnails" view.
Meaning, your code will not work if it has a picture library thumbnail view web part.
A wrong solution would be to append your JS to the end of the page - do this and your code will work, but the thumbnail view will stop working!
The solution for this is rather simple and annoying,
All you have to do is rename the $ sign into something else, like myJQ.
To do this - add this simple line of code at the end of your jQuery JS file:
var $jq = jQuery.noConflict();
and use $jq instead of $.
Note: you should use your own unique key instead of $jq.