Some geek(s) has found a way to overturn Battlelog's emblem editor with a nicely written script.
The script is compatible with a few browsers, but for my tests, I've used firefox. Before installing this lovely script, you need to install greasemonkey to your browser. It's a script manager for your browser. Then you can install the battlelog custom emblem script, and upload your image for your platoon. Here are the steps to follow:
1. Install the Greasemonkey add-on.
2. Install this script: http://userscripts.org/scripts/show/117314
3. Click the green "Install" button at the top.
4. Sign in to Battlelog and go to your platoon.
5. Click the normal "Edit emblem" text.
6. Now click the "USE CUSTOM IMAGE" button at the top of the page.
7. Select the picture you want from your HDD.
8. Click "SAVE EMBLEM" in the popup window. (Don't use the normal SAVE EMBLEM button!)
That was easy right??? Here's an example: http://battlelog.battlefield.com/bf3/platoon/2832655391610407270/