@stypen 
"As short as possible, as long as needed" or whatever it's called in cc ^^
You are right, I think I have been fooled by http://docs.oracle.com/javase/7/docs/api/java/net/URLEncoder.html#encode(java.lang.String, java.lang.String).

@Gorphi 
The method could be used for any filename. Images, folders, etc. So why not using filename as parameter name?