To publish your saved changes to the Website, you need to select "Publish Changes" from the "Tools" menu at the top of the application.

When publishing, you have the option to re-publish all images and/or documents currently in your data.  This is a good idea if you have updated existing images or documents for a large amount of items.  Please note that this will exponentially increase the time it takes for your data to publish, depending on the number of images and/or documents your site has.