How to detect current images-only messages?

[Yves Goergen <no...@unclassified.de>]

Hello,
I keep receiving messages that contain of nothing but composed images.
They're HTML messages with only <img/> tags in them. There seems to be a
rule that checks if the message has *any* image and compares it to its
length. That gave my spam some scores recently but not so today. I
received a message that looks just like the others but has no score at
all due to the fact that it only contains of images.

Is there any way to detect this type of message with SpamAssassin? I
cannot think of a regular expression that would do it, and even if I
could, SA offered no way to match it reliably. (See the line-by-line
problem with 'rawbody' and encoding problems with 'full'.)

-- 
Yves Goergen "LonelyPixel" <no...@unclassified.de>
http://beta.unclassified.de – My web laboratory.