This script will give you the amount of bytes sent by each file type, for example pictures, ASPX pages etc. Great if you need to work with size/performance.

SELECT   
    EXTRACT_EXTENSION( cs-uri-stem ) AS Extension,
    MUL(PROPSUM(sc-bytes),100.0) AS PercentageOfBytes,
    Div(Sum(sc-bytes),1024) as AmountOfMbBytes
INTO
    BytesPerExtension.txt
FROM
    logs\iis\ex*.log
GROUP BY
    Extension
ORDER BY
    PercentageOfBytes
DESC

//Anders