The base64 images are used inside the
<img>tag, same as a normal image url, you will only need to modify the way the img bbcode tag interprets the link, and let it read the base64 image also...
I know the complex images are ablout hundreds characters, and that might be a problem for some people that might not want such a thing into posts of their forums. You could probably allow a option to allow board owners if they want to allow this on their board, or if you guys dont agree with my idea of allowing users to post such images, at least, add an error that tells the user that tries to post such an image, instead of having image code in the imb tag, seen as normal text. After the person trys to preview or submit the image, clear the code inside the img tag, and show an error.
Apologizes for the long and messed up post