----------+-------------------------+----------------------
.htaccess | euc-kr  euc-kr euc-kr   | utf-8  utf-8 utf-8
files     | euc-kr  utf-8  utf-8bom | euc-kr utf-8 utf-8bom
----------+-------------------------+----------------------
text/html | ok      fail   ok       | fail   ok    ok
----------+-------------------------+----------------------
image/jpeg| ok      ok     fail     | ok     ok    fail
----------+-------------------------+----------------------

text/html  서로 문자셋이 같거나 utf-8 bom 이면 정상
image/jpeg 파일이 utf-8 bom 이면 안되고 나머지는 정상

files:
  auto_xxx php file
  all include files
  main.php

image/jpeg => external image files


1. Content-Type: text/html

default_charset euc-kr // .htaccess => charset=euc-kr
  files ansi      // ok
  files utf-8     // fail, display black ??? and more
  files utf-8 bom // ok

default_charset utf-8 // .htaccess => charset=utf-8
  files ansi      // fail, display all black ???
  files utf-8     // ok
  files utf-8 bom // ok


2. Content-Type: image/jpeg // out side image file to sending

default_charset euc-kr // .htaccess
  files ansi      // ok
  files utf-8     // ok
  files utf-8 bom // fail

default_charset utf-8 // .htaccess
  files ansi      // ok
  files utf-8     // ok
  files utf-8 bom // fail