How to prevent others from illegally linking pictures of your website?

How to prevent others from illegally linking pictures of your website?

1. <%OptionExplicit
3. DimstrBuffer, FilePath
4. strBuffer=Request.ServerVariables(HTTP_REFERER)
5. strBuffer=mid(strBuffer,InStr(strBuffer,.)+1)
6. strBuffer=left(strBuffer,InStr(strBuffer,/)-1)
8. FilePath=/HIDDENIMAGES/
10. IfstrBuffer=intels.netthen
11. FilePath=FilePath+Request.QueryString(FName)
12. Else
13. FilePath=/images/chunfeng.jpg
14. EndIf
16. Response.Redirect(FilePath)