Just limitations :
1. Image Formats
You can convert images of the following common images formats:
JPG, PNG, GIF, BMP
The maximum filesize for Base64 is 1,5 MB.
The maximum filesize for CSS Pixels is 350x350 or equal with 122500 pixels.
In case of large images you should consider not to convert them into base64 or CSS pixels.
Not supported IE8 and below.