My mails get 1.6 points (out of max 2 to be classified by spam) from this rule:
SpamAssassin Rule: HTML_IMAGE_ONLY_24
Standard description: HTML: images with 2000-2400 bytes of words
Explanation
This may indicate a message using an image instead of words in order to sidestep text-based filtering.
I have two images embedded in my mail - is that really not possible? How am I even to understand the phrase "with 2000 bytes of words".
Shouldnt it less strict if you embedd the images - as the mails grows larger in size and make it less likely to be spam?