This will replace the mod icon in twitch chat with a green yoshi. I did this because Trihex requested it ;) You can give me other mod icon requests if you want :)
This can be used with the 4 eggs sub icon replace for MAXIMUM SWAG: http://freestyler.ws/style/87057/trihex-4-egg-sub-icon-replacement

NOTE: If you have the Twitch - Dark / Black / Customisable Theme installed and want the mod icon's background to be transparent, you must find the following in the dark twitch theme code and delete them:
".mod{

background-color:#009900!important;
vertical-align:middle!important;
}"

NOTE 2: I have now added compatibilaty with Better TTV, though you must have "Default Chat Tags — BetterTTV replaces the Twitch chat tags with the old JTV ones by default" set to Off.