You have two options.
Put a single text widget in the HEader Widget area, and put both the image html and the title tagline shortcode in there.
Or if you want to have them stacked on mobile, you could put two text widgets in the header widget area put the image in one and the title tagline shortcodes in the second, then set the widget area to be in two columns.
If you don’t have plus, the two columns will have equal width but we could eventually use custom CSS to change that.
If you have plus you can set the width of each widget independently in the header widget area options