Loading message using
<apex:commabndButton value="search" action="{!doSearch}" reRender="out" status="mystatus" />
<apex:outputPanel id="out">
<apex:actionStatus id="mystatus">
<apex:facet name="start">
<apex:outputText value="loading... please wait!"</apex:outputText>
</apex:facet>
<apex:facet name="stop">
<!--show the pageblock or etc... -->
</apex:facet>
if you want to display the image you can do that instead of
<apex:image value="{!$Resource.loading}"</apex:outputText>
find the object name by passing id
adding SSH key using puTTY
<apex:commabndButton value="search" action="{!doSearch}" reRender="out" status="mystatus" />
<apex:outputPanel id="out">
<apex:actionStatus id="mystatus">
<apex:facet name="start">
<apex:outputText value="loading... please wait!"</apex:outputText>
</apex:facet>
<apex:facet name="stop">
<!--show the pageblock or etc... -->
</apex:facet>
if you want to display the image you can do that instead of
<apex:image value="{!$Resource.loading}"</apex:outputText>
find the object name by passing id adding SSH key using puTTY