Summary
This article outlines the Solutions to add a background image to Survey Plus Web Part
Product & Version
KWizCom Survey Plus Standard Evaluation 3.x.xx for SharePoint 2007
KWizCom Survey Plus Standard Evaluation 13.x.xx for SharePoint 2010
Solutions
Solution A
If you use a custom CSS file, you should initialize "CSS File" property in web part settings (see image)

1. Open the "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\wpresources\KWizCom.SharePoint.WebParts.QuickPoll\1.0.0.1__30fb4ddbec95ff8f\ QuickPoll.css" file for editing
2. Add background image to "tableContainer" style:
For Example:
.tableContainer
{
background-color: #e1e1dd;
background: url(/_layouts/images/stsprev.png);
width:100%;
height:100%;
}
Solution B
If you use the standard SharePoint style
1. Open the "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\wpresources\KWizCom.SharePoint.WebParts.QuickPoll\1.0.0.1__30fb4ddbec95ff8f\ SurveyQuestions.xslt" file for editing
2. In the first table element add style attribute: style="background: url(/_layouts/images/stsprev.png);"
For Example:
<TABLE width="100%" border="0" cellspacing="0" cellpadding="0"style="background: url(/_layouts/images/stsprev.png);">