You would need to edit the files and replace the text link with just an image link.
for example, this is the PostNewTopic() sub in forum.asp:
sub PostNewTopic()
%>
<font face="<% =strDefaultFontFace %>" size="<% =strDefaultFontSize %>">
<% if rsCStatus("CAT_STATUS") = 0 or rsFStatus("F_STATUS") = 0 then
if (AdminAllowed = 1) then %>
<a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>"><img src="icon_folder_locked.gif" alt="Category Locked" height=15 width=15 border=0></a> <a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>">New Topic</a>
<% else %>
<img src="icon_folder_locked.gif" alt="Category Locked" height=15 width=15 border=0> Category Locked
<% end if
else
if rsFStatus("F_STATUS") <> 0 then %>
<a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>"><img src="icon_folder_new_topic.gif" alt="New Topic" height=15 width=15 border=0></a> <a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>">New Topic</a>
<% else %>
<img src="icon_folder_locked.gif" alt="FORUM Locked" height=15 width=15 border=0> Forum Locked
<% end if
end if %>
</font>
<%
end sub
You would change it to this:
sub PostNewTopic()
%>
<font face="<% =strDefaultFontFace %>" size="<% =strDefaultFontSize %>">
<% if rsCStatus("CAT_STATUS") = 0 or rsFStatus("F_STATUS") = 0 then
if (AdminAllowed = 1) then %>
<a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>"><img src="YOUR_NEW_TOPIC_ICON.gif" alt="Category Locked" height=15 width=15 border=0></a>
<% else %>
<img src="YOUR_CATEGORY_LOCKED_ICON.gif" alt="Category Locked" height=15 width=15 border=0>
<% end if
else
if rsFStatus("F_STATUS") <> 0 then %>
<a href="post.asp?method=Topic&FORUM_ID=<% =Request.QueryString("FORUM_ID")%>&CAT_ID=<% =Request.QueryString("CAT_ID")%>&Forum_Title=<% =ChkString(Request.QueryString("FORUM_Title"),"urlpath") %>"><img src="YOUR_NEW_TOPIC_ICON.gif" alt="New Topic" height=15 width=15 border=0></a>
<% else %>
<img src="YOUR_FORUM_LOCKED_ICON.gif" alt="FORUM Locked" height=15 width=15 border=0>
<% end if
end if %>
</font>
<%
end sub
you will probably need to change the height and width as well. If you just want to use the default height and width of the icon, remove the height=15 and width=15 from the img tag.