Upload an html entry to Google Docs with base64 encoded images

Using objective-c Google Docs API, I'm uploading to Google Docs html entries (using mime type text/html) with images encoded in base64.

The html img tag appears like:

<img src='data:image/jpeg;base64,myEncodedString' />, 

where myEncodedString is the img data encoded with base64.
The upload is successful, except that the image isn't displayed.
The encoding is right (I've succeeded in decoding the string back to the original image).
The rest of document is well displayed with the right formatting (font, size, color etc, set in the html).

Is a Google Docs server problem? or?

EDIT

I'm trying to use base64 encoding 'cause the images are local ones.