Visualforce page messages and icons. Error, caution, info, warning, fatal

Page Messages & Icons.java

<apex:page >
<apex:pageBlock title="Small Messages">
    <apex:pageMessage summary="This is a warning" severity="confirm" strength="1" />
    <apex:pageMessage summary="This is a piece of information" severity="info" strength="1" />  
    <apex:pageMessage summary="This is a warning" severity="warning" strength="1" /> 
    <apex:pageMessage summary="This is an error" severity="error" strength="1" /> 
    <apex:pageMessage summary="This is a fatal message" severity="fatal" strength="1" />
</apex:pageBlock>
<apex:pageBlock title="Medium Messages">
    <apex:pageMessage summary="This is a warning" severity="confirm" strength="2" />
    <apex:pageMessage summary="This is a piece of information" severity="info" strength="2" />  
    <apex:pageMessage summary="This is a warning" severity="warning" strength="2" /> 
    <apex:pageMessage summary="This is an error" severity="error" strength="2" /> 
    <apex:pageMessage summary="This is a fatal message" severity="fatal" strength="2" />
</apex:pageBlock>
<apex:pageBlock title="Large Messages">
    <apex:pageMessage summary="This is a warning" severity="confirm" strength="3" />
    <apex:pageMessage summary="This is a piece of information" severity="info" strength="3" />  
    <apex:pageMessage summary="This is a warning" severity="warning" strength="3" /> 
    <apex:pageMessage summary="This is an error" severity="error" strength="3" /> 
    <apex:pageMessage summary="This is a fatal message" severity="fatal" strength="3" />
</apex:pageBlock> 
<apex:image value="/img/msg_icons/confirm16.png" />
<apex:image value="/img/msg_icons/confirm24.png" />
<apex:image value="/img/msg_icons/confirm32.png" />
<apex:image value="/img/msg_icons/error16.png" />
<apex:image value="/img/msg_icons/error24.png" />
<apex:image value="/img/msg_icons/error32.png" />
<apex:image value="/img/msg_icons/warning16.png" />
<apex:image value="/img/msg_icons/warning24.png" />
<apex:image value="/img/msg_icons/warning32.png" />
<apex:image value="/img/loading32.gif" />
</apex:page>