Because I can read many dicussions around this big grey box or featured image, let me give to you my solution for getting a fixed image and a fixed title for the homepage of the Structure theme.
In Article>Category, create a Welcome category.
In Appareance>Theme Options, select the Welcome category as the one to use for the front page featured post.
Create an article of this category with a featured post. Its title will become the welcome page Title and this image will become your fixed image.
If you don't use the Welcome category for all the other articles, this will remain without preventing you to get the new articles in the Homepage.
If you want to change the image or the title just modify the article.
If you create a new article of this welcome category without a featured post, you will see the big grey box again.
Voila,I hope this is clear enough.
The blog I need help with is tassiopee.wordpress.com.