Image is showing up in internal visualforce page but not showing up in external visualforce site page.I have stored image in document and made it externally available and document folder is accessible to all users

Here is the image formula field.

IF( ISPICKVAL(Status__c,"Up"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4D", "Green"), 
IF ( ISPICKVAL(Status__c,"Down"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4N", "Red"), 
IMAGE("/servlet/servlet.FileDownload?file=015t00000004p4I", "Yellow")))

Here is the part of visualforce page

    <apex:dataTable value="{!OutList}" var="o"  rows="11" styleClass="table" > 
         <apex:column value="{!o.Service__c}" headerValue="Service" headerClass="colHeadr"/>
         <apex:column value="{!o.Status__c}" headerValue="Status"  headerClass="colHeadr"/>
          <apex:column value="{!o.Image__c}" headerValue="Image"  headerClass="colHeadr"/>
     </apex:dataTable>

Image is showing up in internal visualforce page but not showing up in external visualforce site page.I have stored image in document and made it externally available and document folder is accessible to all users. Also provided View All access to Document object under site profile settings. Here is the image formula field.

IF( ISPICKVAL(Status__c,"Up"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4D", "Green"), 
IF ( ISPICKVAL(Status__c,"Down"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4N", "Red"), 
IMAGE("/servlet/servlet.FileDownload?file=015t00000004p4I", "Yellow")))

Here is the part of visualforce page

    <apex:dataTable value="{!OutList}" var="o"  rows="11" styleClass="table" > 
         <apex:column value="{!o.Service__c}" headerValue="Service" headerClass="colHeadr"/>
         <apex:column value="{!o.Status__c}" headerValue="Status"  headerClass="colHeadr"/>
          <apex:column value="{!o.Image__c}" headerValue="Image"  headerClass="colHeadr"/>
     </apex:dataTable>

Image is showing up in internal visualforce page but not showing up in external visualforce site page.I have stored image in document and made it externally available and document folder is accessible to all users

Here is the image formula field.

IF( ISPICKVAL(Status__c,"Up"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4D", "Green"), 
IF ( ISPICKVAL(Status__c,"Down"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4N", "Red"), 
IMAGE("/servlet/servlet.FileDownload?file=015t00000004p4I", "Yellow")))

Here is the part of visualforce page

<apex:dataTable value="{!OutList}" var="o"  rows="11" styleClass="table" > 
     <apex:column value="{!o.Service__c}" headerValue="Service" headerClass="colHeadr"/>
     <apex:column value="{!o.Status__c}" headerValue="Status"  headerClass="colHeadr"/>

<apex:column value="{!o.Image__c}" headerValue="Status" headerClass="colHeadr"/> </apex:dataTable>

Image is showing up in internal visualforce page but not showing up in external visualforce site page.I have stored image in document and made it externally available and document folder is accessible to all users

Here is the image formula field.

IF( ISPICKVAL(Status__c,"Up"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4D", "Green"), 
IF ( ISPICKVAL(Status__c,"Down"), IMAGE("/servlet/servlet.FileDownload?file=015t00000004k4N", "Red"), 
IMAGE("/servlet/servlet.FileDownload?file=015t00000004p4I", "Yellow")))

Here is the part of visualforce page

    <apex:dataTable value="{!OutList}" var="o"  rows="11" styleClass="table" > 
         <apex:column value="{!o.Service__c}" headerValue="Service" headerClass="colHeadr"/>
         <apex:column value="{!o.Status__c}" headerValue="Status"  headerClass="colHeadr"/>
          <apex:column value="{!o.Image__c}" headerValue="Image"  headerClass="colHeadr"/>
     </apex:dataTable>