Will changes to your code automatically appear on the web if you've already transferred your files to the server?

You don't need to upload every file just the one you made changes too.

Lindsay,

Changes to your code on your local machine will not be automatically populated on the web. If you are using an FTP like Filezilla then you will need to load those new images into the folders you are hosting on your server. If you are running an instance and lets say hosting on Amazon Web Services you will have to load those image files onto your instance, possibly by pulling an updated git repo.

Nathan

You need to upload any files you've added or changed; they will not automatically update themselves. This allows you to build a new feature for your site locally and then push it live when you're finished.

However, it's interesting that you mention this. If you open up FileZilla and connect to a server, then right-click on a file in the right pane and select Edit, FileZilla will download the file to a temp directory on your computer and open it up in your default text editor. Whenever you edit and save this file (the temp file), FileZilla will automatically upload it. It's a useful feature for tweaking a file and seeing its effects live. It's only a temporary file, though; there's no way to make your entire project work like this.