I believe that InfoPath's way of representing images in rich text is exclusive to InfoPath and won't work as-is in any browser.
What you need to do is iterate through all of the <img> tags and replace the value of the src="" attribute with a value like the following:
data:image/extension;base64value
Extension can be determined based on the first three characters of the base64 value:
R0lG - gif
/9j/ - jpg
iVBO - png
SUkq - tif
(other) - bmp
And once you've retrieved the base64 value from the xd:inline attribute, I'd suggest removing the xd:inline attribute in order to minimize the size of the HTML file.