At first, they seem like your average junk email, containing share tips or an advertisement for Viagra, along with a small, slightly garbled picture.
But this, experts say, is the spam that could bring the internet to a virtual standstill this year.
To bypass anti-spam software, the emails use an image instead of text.
In the past six months, this "image spam" has seen a massive increase and now represents 35 per cent of all junk email, according to security software firm F-Secure.