HAProxy : Http-request deny working for http but not https urls

i am using haproxy as middle server for routing my request to different proxy servers.
So i for particular reasons i was trying to block all png files with my haproxy server . problem is if i access any http domain with .png at end it works perfectly fine it blocks it… but if i access https domain it dosnt block it and lets it through kindly help. i cannot fathom right now because its perfectly routing https requests to the out server but its not blocking https requests with .png at end here is my haproxy config below

```
    #Forward HaProxy Config 
 global
 daemon
 maxconn 300000

defaults
 mode http
 timeout connect 10000ms
 timeout client 50000ms
 timeout server 50000ms

listen stats
 bind :9999
 stats enable
 stats hide-version
 stats uri /stats
 stats auth admin:admin123
frontend pro_in1
 bind 0.0.0.0:21001
 acl im path_end .png
 http-request deny if im
 use_backend pro_out1
backend pro_out1
 cookie SERVERID insert indirect nocache
 option httpclose
 option forwardfor header X-Client
 balance roundrobin
 mode http
 server ip-1 xxxxxxxxxxx:7777
```