Probelem about image size and dimensions

[ChengGong]

Hi Diez,

They do not allow me to do what u said above.
so I do not have any idea what is supposed to do.
however i am think that if I can get the id of the image, i have chance
to modify it.
This is what i programed but it is an empty page, I but it in images
folder
<dtml-var standard_html_header>

<h1>File Library</h1>

<table>
  <tr>
    <th><a href="&dtml-URL0;?sort=name">File</a></th>
    <th><a href="&dtml-URL0;?sort=date">Last Modified</a></th>
   </tr>

<dtml-if expr="_.has_key('sort') and sort=='date'">
  <dtml-in expr="objectValues(['Image'])"
           sort="bobobase_modification_time" reverse>
    <tr>
       <td><a href="&dtml-absolute_url;"><dtml-var
title_or_id></a></td>
       <td><dtml-var bobobase_modification_time fmt="aCommon"><td>
    </tr>
  </dtml-in>
<dtml-else>
  <dtml-in expr="objectValues(['Image'])" sort="id">
    <tr>
       <td><a href="&dtml-absolute_url;"><dtml-var
title_or_id></a></td>
       <td><dtml-var bobobase_modification_time fmt="aCommon"><td>
    </tr>
  </dtml-in>
</dtml-if>

</table>

<dtml-var standard_html_footer>

is there any mistake?
How ever thank you alot Diez. Your comments and suggestion are helpful.

P.S. i am doing my internship in a commercial company:(, create
external method is not allowed in my situation

Cheng