Your image and video content is working since bot framework supports various media.
Adaptive card is a media in itself. You need to create content of adaptive card type and then you can render it inside any prompt dialog.
You can install Adaptive Card Nuget Package by typing the following in Tools > Nuget > Package Manager Console
:
Install-Package AdaptiveCards -Version 1.2.4
Or you can also directly Install the package - AdaptiveCards 1.2.4
from Manage Nuget Package
option.
Do not install - Microsoft.AdaptiveCards
, it's an old version.
After doing this, you can refer this blog for using adaptive cards.