Salve ragazzi , ho un problema e spero che mi aiuterete a risolvere ...
Allora io ho questo blog e devo cambiare lo sfondo mettendo al posto dell'immagine l'annuncio pubblicitario.
Questo precisamente


Mi potreste spiegare come inserirlo ?


Il codice html del blog è :

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html>
<html b:version='2' class='v2' expr:dir='data:blog.languageDirection' xmlns='http://www.w3.org/1999/xhtml' xmlns:b='http://www.google.com/2005/gml/b' xmlns:data='http://www.google.com/2005/gml/data' xmlns:expr='http://www.google.com/2005/gml/expr'>
<head>
<meta content='IE=EmulateIE7' http-equiv='X-UA-Compatible'/>
<b:if cond='data:blog.isMobile'>
<meta content='width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0' name='viewport'/>
<b:else/>
<meta content='width=1100' name='viewport'/>
</b:if>
<b:include data='blog' name='all-head-content'/>
<title><data:blog.pageTitle/></title>

<b:skin><![CDATA[/*
-----------------------------------------------
Blogger Template Style
Name: Ethereal
Designer: Jason Morrow
URL: jasonmorrow.etsy.com
----------------------------------------------- */

/* Variable definitions
====================
<Variable name="keycolor" description="Main Color" type="color" default="#000000" value="#000000"/>

<Group description="Body Text" selector="body">
<Variable name="body.font" description="Font" type="font"
default="normal normal 13px Arial, Tahoma, Helvetica, FreeSans, sans-serif" value="normal normal 13px Arial, Tahoma, Helvetica, FreeSans, sans-serif"/>
<Variable name="body.text.color" description="Text Color" type="color" default="#666666" value="#666666"/>
</Group>

<Group description="Background" selector=".body-fauxcolumns-outer">
<Variable name="body.background.color" description="Outer Background" type="color" default="#fb5e53" value="#fb5e53"/>
<Variable name="content.background.color" description="Main Background" type="color" default="#ffffff" value="#ffffff"/>
<Variable name="body.border.color" description="Border Color" type="color" default="#fb5e53" value="#fb5e53"/>
</Group>

<Group description="Links" selector=".main-inner">
<Variable name="link.color" description="Link Color" type="color" default="#2198a6" value="#2198a6"/>
<Variable name="link.visited.color" description="Visited Color" type="color" default="#4d469c" value="#4d469c"/>
<Variable name="link.hover.color" description="Hover Color" type="color" default="$(link.color)" value="$(link.color)"/>
</Group>

<Group description="Blog Title" selector=".header h1">
<Variable name="header.font" description="Font" type="font"
default="normal normal 60px Times, 'Times New Roman', FreeSerif, serif" value="normal normal 60px Times, 'Times New Roman', FreeSerif, serif"/>
<Variable name="header.text.color" description="Text Color" type="color" default="#ff8b8b" value="#ff8b8b"/>
</Group>

<Group description="Blog Description" selector=".header .description">
<Variable name="description.text.color" description="Description Color" type="color"
default="#666666" value="#666666"/>
</Group>

<Group description="Tabs Text" selector=".tabs-inner .widget li a">
<Variable name="tabs.font" description="Font" type="font"
default="normal normal 12px Arial, Tahoma, Helvetica, FreeSans, sans-serif" value="normal normal 12px Arial, Tahoma, Helvetica, FreeSans, sans-serif"/>
<Variable name="tabs.selected.text.color" description="Selected Color" type="color" default="#ffffff" value="#ffffff"/>
<Variable name="tabs.text.color" description="Text Color" type="color" default="$(body.text.color)" value="$(body.text.color)"/>
</Group>

<Group description="Tabs Background" selector=".tabs-outer .PageList">
<Variable name="tabs.selected.background.color" description="Selected Color" type="color" default="#ffa183" value="#ffa183"/>
<Variable name="tabs.background.color" description="Background Color" type="color" default="#ffdfc7" value="#ffdfc7"/>
<Variable name="tabs.border.bevel.color" description="Bevel Color" type="color" default="#fb5e53" value="#fb5e53"/>
</Group>

<Group description="Post Title" selector="h3.post-title, h4, h3.post-title a">
<Variable name="post.title.font" description="Font" type="font"
default="normal normal 24px Times, Times New Roman, serif" value="normal normal 24px Times, Times New Roman, serif"/>
<Variable name="post.title.text.color" description="Text Color" type="color" default="#2198a6" value="#2198a6"/>
</Group>

<Group description="Gadget Title" selector="h2">
<Variable name="widget.title.font" description="Title Font" type="font"
default="normal bold 12px Arial, Tahoma, Helvetica, FreeSans, sans-serif" value="normal bold 12px Arial, Tahoma, Helvetica, FreeSans, sans-serif"/>
<Variable name="widget.title.text.color" description="Text Color" type="color" default="$(body.text.color)" value="$(body.text.color)"/>
<Variable name="widget.title.border.bevel.color" description="Bevel Color" type="color" default="#dbdbdb" value="#dbdbdb"/>
</Group>

<Group description="Accents" selector=".main-inner .widget">
<Variable name="widget.alternate.text.color" description="Alternate Color" type="color" default="#cccccc" value="#cccccc"/>
<Variable name="widget.border.bevel.color" description="Bevel Color" type="color" default="#dbdbdb" value="#dbdbdb"/>
</Group>

<Variable name="body.background" description="Body Background" type="background"
color="$(body.background.color)" default="$(color) none repeat-x scroll top left" value="#fb5e53 url(//www.blogblog.com/1kt/ethereal/birds-2toned-bg.png) repeat-x scroll top center"/>
<Variable name="body.background.gradient" description="Body Gradient Cap" type="url"
default="none" value="none"/>
<Variable name="body.background.imageBorder" description="Body Image Border" type="url"
default="none" value="url(//themes.googleusercontent.com/image?id=0BwVBOzw_-hbMNjViMzQ0ZDEtMWU1NS00ZTBkLWFjY2EtZjM5YmU4OTA2MjB m)"/>
<Variable name="body.background.imageBorder.position.left" description="Body Image Border Left" type="length"
default="0" value="300px"/>
<Variable name="body.background.imageBorder.position.right" description="Body Image Border Right" type="length"
default="0" value="299px"/>
<Variable name="header.background.gradient" description="Header Background Gradient" type="url" default="none" value="none"/>
<Variable name="content.background.gradient" description="Content Gradient" type="url" default="none" value="url(//www.blogblog.com/1kt/ethereal/bird-2toned-blue-fade.png)"/>

<Variable name="link.decoration" description="Link Decoration" type="string" default="none" value="none"/>
<Variable name="link.visited.decoration" description="Link Visited Decoration" type="string" default="$(link.decoration)" value="$(link.decoration)"/>
<Variable name="link.hover.decoration" description="Link Hover Decoration" type="string" default="underline" value="underline"/>

<Variable name="widget.padding.top" description="Widget Padding Top" type="length" default="15px" value="15px"/>

<Variable name="date.space" description="Date Space" type="length" default="15px" value="15px"/>

<Variable name="post.first.padding.top" description="First Post Padding Top" type="length" default="0" value="0"/>

<Variable name="mobile.background.overlay" description="Mobile Background Overlay" type="string" default="" value=""/>
<Variable name="mobile.background.size" description="Mobile Background Size" type="string" default="auto" value="auto"/>

<Variable name="startSide" description="Side where text starts in blog language" type="automatic" default="left" value="left"/>
<Variable name="endSide" description="Side where text ends in blog language" type="automatic" default="right" value="right"/>
*/

/* Content
----------------------------------------------- */
body {
font: $(body.font);
color: $(body.text.color);
background: $(body.background);
}

html body .content-outer {
min-width: 0;
max-width: 100%;
width: 100%;
}

a:link {
text-decoration: $(link.decoration);
color: $(link.color);
}

a:visited {
text-decoration: $(link.visited.decoration);
color: $(link.visited.color);
}

a:hover {
text-decoration: $(link.hover.decoration);
color: $(link.hover.color);
}

.main-inner {
padding-top: $(date.space);
}

.body-fauxcolumn-outer {
background: transparent $(body.background.gradient) repeat-x scroll top center;
}

.content-fauxcolumns .fauxcolumn-inner {
background: $(content.background.color) $(content.background.gradient) repeat-x scroll top left;
border-left: 1px solid $(body.border.color);
border-right: 1px solid $(body.border.color);
}

/* Flexible Background
----------------------------------------------- */
.content-fauxcolumn-outer .fauxborder-left {
width: 100%;
padding-left: $(body.background.imageBorder.position.left);
margin-left: -$(body.background.imageBorder.position.left);
background-color: transparent;
background-image: $(body.background.imageBorder);
background-repeat: no-repeat;
background-position: left top;
}


.content-fauxcolumn-outer .fauxborder-right {
margin-right: -$(body.background.imageBorder.position.right);
width: $(body.background.imageBorder.position.right);
background-color: transparent;
background-image: $(body.background.imageBorder);
background-repeat: no-repeat;
background-position: right top;
}


/* Columns
----------------------------------------------- */

.content-inner {
padding: 0;
}

/* Header
----------------------------------------------- */
.header-inner {
padding: 27px 0 3px;
}

.header-inner .section {
margin: 0 35px;
}

.Header h1 {
font: $(header.font);
color: $(header.text.color);
}

.Header h1 a {
color: $(header.text.color);
}

.Header .description {
font-size: 115%;
color: $(description.text.color);
}

.header-inner .Header .titlewrapper,
.header-inner .Header .descriptionwrapper {
padding-left: 0;
padding-right: 0;
margin-bottom: 0;
}

/* Tabs
----------------------------------------------- */
.tabs-outer {
position: relative;
background: transparent;
}

.tabs-cap-top, .tabs-cap-bottom {
position: absolute;
[/HTML]

Il codice non l'ho scritto tutto perchè occupava troppi caratteri e credo si trovi in questa parte la parte da modificare

Il codice html dello sfondo pubblicitario è
<div style="background:url('http://www.affiliago.it/accounts/default1/banners/SKIN_BAKECA.jpg') no-repeat fixed; background-position:top center; width:100%; margin:0px; height:100%; padding:0px;padding-top:85px; z-index:0; position:relative">

</div>

Grazie in anticipo