What kind of receiver can be used to receive and decode SSTV using the Digital Radio Mondiale (DRM) protocol?
Why Digital SSTV using the DRM protocol packs a digital multi-carrier (OFDM) signal into about 2.3 kHz of audio bandwidth, which is exactly what an HF SSB channel provides. The receiver demodulates the sideband signal to audio, and software on a computer or sound card interface decodes the OFDM carriers back into the image file. So any standard SSB transceiver, tuned as for voice and with stable tuning, is all the hardware you need.
Watch out AM is tempting because commercial shortwave DRM broadcasting occupies AM broadcast channels, but ham digital SSTV is carried in an SSB passband; CDMA is a cellular access method and AREDN is an amateur microwave mesh networking system, neither of which decodes HF images.
Digital SSTV rides in a 2.3 kHz voice channel, so the answer is the same rig you use for HF voice: SSB.