This blog post - Upload Files in a Browser Using Drag and Drop - describes a great add-on for Firefox - that lets you drag and drop files to your browser instead of either typing the complete file path, or browsing to it. You can even drag and drop multiple files at a time.
Even my wife complains about the awkwardness of attaching files to Gmail messages. I've suggested zipping up multiple files so she only has to attach one zip file, but to her, that's just adding complexity. I think she'll be happy with this new trick. (Once I get around to installing it on her computer and explaining how to use it.)