The image is actually a background image, it’s a feature of the theme we are using. It’s basically made out of modules one after another, where you can set the background color, image, padding etc.. for each module.
You can either use a similar theme, or I believe there are visual editors supporting this, like: Visual Composer or Live composer
The layout issue is probably related to your site and assets cache. If it’s different on the back-end then it means that the changes have been saved, but on the front-end you are still getting an older version of the CSS files.
Make sure to clear your site cache, page cache, browser cache, minify cache and CDN (cloudflare, maxcdn etc..), and also make sure to reload your page with CTRL + F5 or CTRL + R to refresh the local browser cache as well.
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