Hi There,
Please navigate to Appearance > Customize > Layout and Design and set your Content Layout to Content Left, Sidebar Right, saved.
Navigate to Appearance > Widgets and use the Main Sidebar for adding widgets (e.g. your image code)
Navigate to Appearance > Sidebars and remove the BlueprintSideBar from the Blog index page, from now on use the Main Sidebar for adding widget.
Use a Blank - No Container, Header | Footer page template to your pages if you don’t want the pages to have a sidebar.
Hope it helps,
Cheers!