Not too sure what you're doing with the addtoArray stuff, but just to pass another parameter into your template is simple:

First add it to your call-template statement:

<xsl:call-template name="buildArray">
<xsl:with-param name="arrayNodes" select="umbraco.library:GetMedia($imageRoot, 'true')/node/data[@alias='umbracoFile']"/>
<xsl:with-param name="imgCaption" select="umbraco.library:GetMedia($imageRoot, 'true')/node/data[@alias='yourCaptionFieldName']"/>
</xsl:call-template>

Then add it to the buildArray template

<xsl:template name="buildArray" >
<xsl:param name="arrayNodes"/>
<xsl:param name="imgCaption"/>
 <xsl:for-each select="$arrayNodes">
    <xsl:value-of select="myFuncs:addtoArray(string(./text()))"/>
    Caption:  <xsl:value-of select="$imgCaption"/>
 </xsl:for-each>
</xsl:template>

Hey Tom,

Thanks for the quick response buddy. great response too, but still not working. 

yr xslt above nearly works.  it brings back a random image but the caption does not change.

you see i uploaded images to my media section and gave them a caption too.  So what i want is to bring back a random image and its associated caption.

here's the complete xslt if it helps:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:Stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]>

<xsl:stylesheet
    version="1.0"
    xmlns:msxsl="urn:schemas-microsoft-com:xslt" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:msxml="urn:schemas-microsoft-com:xslt"
    xmlns:umbraco.library="urn:umbraco.library"
    xmlns:myFuncs="urn:my-scripts"
    exclude-result-prefixes="msxml myFuncs umbraco.library">


<xsl:output method="xml" omit-xml-declaration="yes" indent="yes"/>

<xsl:param name="currentPage"/>

<xsl:variable name="imageRoot"     select="$currentPage/ancestor-or-self:: node[@level = 1]/data [@alias = 'frontPageImages']"/>

<msxsl:script implements-prefix="myFuncs" language="JavaScript">
<![CDATA[

var myArray = new Array();

function random(){    
    var index = Math.floor(Math.random() * myArray.length);   
    return myArray [index];
}

function addtoArray(item){
    myArray.push(item);
}

]]>

</msxsl:script>

<xsl:template match="/">


<xsl:call-template name="buildArray">
<xsl:with-param name="arrayNodes" select="umbraco.library:GetMedia($imageRoot, 'true')/node/data[@alias='umbracoFile']"/>
<xsl:with-param name="imgCaption" select="umbraco.library:GetMedia($imageRoot, 'true')/node/data[@alias='caption']"/>
</xsl:call-template>



<img>
<xsl:attribute name="src">
<xsl:text>/umbraco/imagegen.ashx?image=</xsl:text>
   <xsl:value-of select="myFuncs:random()"/>
<xsl:text>&amp;width=400</xsl:text>
</xsl:attribute>
<xsl:attribute name="style">
<xsl:text>width:400px;</xsl:text>
</xsl:attribute>
</img>
<p id="caption">
<xsl:value-of select="$currentPage/data[@alias='caption']"/>
</p>


</xsl:template>

<xsl:template name="buildArray" >
<xsl:param name="arrayNodes"/>
    <xsl:for-each select="$arrayNodes">
        <xsl:value-of select="myFuncs:addtoArray(string(./text()))"/>
    </xsl:for-each>

</xsl:template>
</xsl:stylesheet>

have you tried
<xsl:value-of select="umbraco.library:GetMedia($imageRoot, 'true')/node/data[@alias='caption']"/>
instead of
<xsl:value-of select="$currentPage/data[@alias='caption']"/>

Many thanks dudes...you guys are terrific.

Sascha your code is Excellent man!!! thanx.

Javascript works perfectly in a normal  web page with no xslt so i know its correct. i mean it gets random image and its corresponding caption on page refresh.

however when used inconjunction with the xslt it doesn't seem to refresh or regenerate a random number.  The image and caption remain as per first page request.

I'm still investigating this but 98% there. thanks to you.

>sajid

Thanx Sascha...it worked.

changed: <xsl:value-of select="myFuncs:addtoArray(current()/data[@alias='umbracoFile'], current()/data[@alias='caption'])"/>

to:  <xsl:value-of select="myFuncs:addtoArray(string(./data[@alias='umbracoFile']),string(./data[@alias='caption']))"/>

is working on a reply...