Revamped Image Option

Closes #66. Also separated the styles into different CSS files. We
should do this with the others too.
Fixed Bug Where `show_font_size` Was Not Working

Closes #70
Fixed Bug Where Resetting a Font Option to Defaults Gives out Errors

Fixes #69
Added New Parameter `preview_text` for the `font` Option for Changing the Preview Text

Closes #63