If you are a ham radio operator, the idea of sending pictures and data over voice channels is nothing new. Hams have lots of techniques for doing that and — not so long ago — even most data transmissions were over phone lines. However, now everyone can get in on the game thanks to the cheap availability of software-defined radio. Several commercial shortwave broadcasters are sending encoded data including images and even entire web pages. You can find out more at the Swradiogram website. You can also find step-by-step instructions.
WINB in Pennsylvania and WRMI Florida both have shows that include interspersed data. To play along, you’ll need a decoder like Fldigi or TIVAR. If you don’t have sufficient radio gear, you can probably borrow some from the Internet.