1. depends on the images mentioned
2. you can use a caching plugin; some also provide css and js minify-cation; just don’t over-minify as that will break the theme (and other things);
3. this is in the FAQs:
Make sure the “Site Title” and “Tagline” fields are filled in under Settings > General, otherwise you will see a stray dash in the browser title.
If you do wish to hide the previously filled in site title and tagline from the site header area, just set the option to anything but “Site title and description” — logo (if you have one), clickable header (if you’ve set a header image) or empty will all do.