1: Go to emblemsbf.com and select one of the many emblems. One the emblem page, simply highlight the code and copy it.
2: Open Battlelog and get into the Emblem creator. Create a new emblem, and then hit Control + Shift + J in Google Chrome (Ctrl-Shift-K for Firefox, F12 in Internet Explorer), which will open up the console for the web page.
3: Go to the bottom of the console page, and paste the code (Control + V) that you copied from the emblem page. Hit Enter, and the emblem should now appear fully created in your Battleog.
http://bf4central.com/2013/11/add-awesome-battlefield-4-emblems-fast-easy/