Irule maintanance page with ifile

This mine, working on my BIGIP. If you want to use ifile, you need to get ifile name. Below, I launch 404 ifile (404.html page) and I request each picture in this html page with ifile.

when HTTP_REQUEST {

            used for 404 error page. Send each image png file to 404 HTML page.
            switch -glob [string tolower [HTTP::uri]]
            {
            "*.png"
            {
            Remove slash and png on /imagexxxx.png and call iFile imagexxxxx
            HTTP::respond 200 content [ifile get [getfield [string range [HTTP::uri] 1 end] "." 1]]
            }
            default {}
            }
            }

when HTTP_RESPONSE {
if { [HTTP::status] == 404 } {
            log local0. "Error 404"
            ifile 404 is the HTML page with a reference to photoxxxx.png
            HTTP::respond 200 content [ifile get 404]
   }