Create custom front page without adding content
In your case, yes you can create settings form, where admin will load background images, logo and enter description. But why you want use picture module? You can define new variables in hook preprocess_page for front page. Where in variable you put url to background image, url to logo, descriptions. After in front page template file, set url background to our block, logo and place descriptions.
Finally add styles to block class or id in css file for align background at the block. For this you can use something like this:

.your-class {
    background: transparent url("path/to/background.jpg") no-repeat scroll 50% 50% / cover;
    width: 100%;
}


background url you add in template. I write path to url in code for quick example, you can place this code in some div, add correct url and see result.