First time my site went online and Problems :)

hi ,

Last day i made my site online. After putting it online first thought came to my mind that if i make some changes in my local machine then i will have to upload all the files all again ????

Or should i make my changes online ??? What about other people viewing those pages ? Is there any Good way to do all this ??

1 last thing here is my Sample site http://www.sanoraonline.com/ . On th front page u will see the Image rotator but the second image in the rotator seem to be a bit short in width. Here is the code which i took from Template.php. What should i add to increase the Width ? (Sorry i dnt knw php :( )

drupal_add_js(path_to_theme('amadou') . '/innerfade/jquery.innerfade.js');
drupal_add_js('
$(document).ready(function(){
$("#header-image img").show();
$("#header-image").innerfade({
speed: 1000,
timeout: 6000,
type: "sequence",
containerheight: "250px"

});
});
', inline);

I will be really thankfull if someone helps me resolve these issues :)