Well programs like Cooledit and probably the free Audiacity will try to play any file as a wav file, when the file ending is .wav
Then you can record it on tape. You can then record the audio file on a PC as an uncompressed wavefile and then just rename it to .jpg or whatever. But I doubt it works, because casette tapes can get very lossy with audio.
10 years ago I expermented with "embedding" images in to wave files and vice versa. The result was a mishmash of audio and images. If a played it with an aduio player, the image parts where noise but the audio part was okay. If I loaded the picture in a pictur viewer, the audio part looked like noise, and the image part was okay.
But I guess what you want is a datasette, just as TSPenguin said.