JQuery (re)-Processing of html element returned by ajax framework

I have the following question,

Does JQuery (re)-Processing of html elementa returned by ajax framework happens automatically?

Example:
1) I load an image gallery and upon loading a bunch of javascripts is called to process thumbnails, create toolbars, etc.
2) I have an ajax-enabled select box to change library, i.e. list of thumbnails images will get reloaded.
3) Once thumbnails are reloaded by selection change in step 2, will the scripts that were called in step (1) get automatically called? or do i have to call them explicitly?

Anyway this an exercise, I intend to accomplish.