if (/\<img src=(???)-disclose.gif(.*)\>/i) {
         $_ = "";

##</code><code>##

lc; #Much more efficient than having the regex do it
s/\<img\s*src\s*=[^->]-disclose.gif[^>]*>//g; 
#more effecient to use a substitution

##</code><code>##

(.*)\>