yes u r right.u must use filesystemobject.
here i send a program to find out the file type whether it is "gif" or "jpg"
set objfso=server.CreateObject("Scripting.FileSystemObject"

set objdrivec = objfso.GetDrive("C:"

set objroot= objdrivec.RootFolder
For each objFile in objroot.Files
dim extention
dim filename
filename=mid(objFile.Name,1,instrrev(objFile.Name,".",len(objFile.Name))-1)
extention=mid(objFile.Name,instrrev(objFile.Name,".",len(objFile.Name))+1,4)
'Response.Write(objFile.Name & "<br>"
if lcase(extention)="gif" or lcase(extention)="jpg" then
Response.Write("File name:" & objFile.Name&"<br>" )
end if
if lcase(filename)="leafbg" and lcase(extention)="jpg" then
Response.Write "JPEG FILE" & "<br>"
end if
next
i hope this may help u to solve the problem
with regards
webspy