>...
>Hi,
> I have setup SA 3.1 under FC4, which is working quite well. However,
>one type of message that still gets through is a series of mails that are
>made up of no text other than a varying subject, then a picture, which is
>black text on white, which looks exactly like an ordinary email. Obviously
>SA can't read the message since it is an image, but is there a way to make a
>rule that blocks a mail where there is an image only, no text?
>
>Regards,
>Tony
>...
Yes, this is a problem, but a simple rule like you describe is overly
broad; What happens when my wife sends our children snapshots from with her
cell phone (which causes exactly this case - though the pictures are in color).
Maybe other service providers add some text, and I know she *could* attach a
message, but seldom does (she just gives it a title like "Nice statue",
"Pretty bird" or similar short, almost meaningless "Subject:" lines).
Also, you obviously haven't seen the multi-color text on colored
background spams with thin (one pixel) randomly angled lines going through
the text to confuse the commercial services who do already attempt character
recognition in images. Maybe some enterprising individual will try to
write a plug-in for SA to do this (still, it would be computationally
expensive for sites getting many images).
Once again, digests, net tests (DSN, RCVD, etc.) and header rules
are your best defense for now (also, AFAICT, ".png" files appear mostly
in spam, JPEG and TIFF files are sent by most camera phones, so maybe a rule
on image type would help some, but spammers would quickly adapt, and nearly
all image formats have legitimate uses - let's not argue about ".gif"s here).
Paul Shupak
[EMAIL PROTECTED]