I have got to re-install MMSSTV I used to use it all the time to send and receive SSTV on 40 and 20. I need to see if I can get it to work on my set-up.
I have MMSSTV working for receiving. There's still lots of analog SSTV on 20, but the crowd on 40 seems to prefer digital these days. (I have EasyPal installed for receiving digital, but it's hard to get a complete file received if you can't send requests for missed blocks, so I pretty much ignore digital SSTV unless I've got a huge signal coming in.)
For anyone who doesn't know, there are three ways, more or less, to get a digital decoding program to work with an SDR program on Windows.
The first is to check if your audio mixer control program offers you a "stereo mix" selection in the input panel. Most used to, then it went out of vogue for a while, although sometimes it was just hidden and needed to be enabled. I think my last few systems had it enabled by default again. This is the easiest method, but if you have anything else on your system making sound, it'll screw up your decodes.
The second one is to use a "virtual audio cable" driver that provides a device that you can assign as the SDR software's audio output device and another device that you can assign as the decoder's audio input device. This device should also show up in your Windows mixer input panel, so you can select it as a source to listen to so that you can monitor your SDR audio at all times, rather than switching inputs just to decode. For years, the only virtual audio cable drivers were commercial, but there are now donationware alternatives available from
http://vb-audio.pagesperso-orange.fr/Cable/index.htm
The final alternative is, of course, to install a second sound card and connect a cable from its input to the output of the main sound card. But this poses the same interference potential as using the "stereo mix" input.