Some things do that with no signal. OBS just hangs on the last frame. If OBS is getting a signal from a box that does that, just give that box a signal.
Or do you want to detect that image and use that detection to trigger something? For that, there's the Advanced Scene Switcher plugin:
This plugin will allow you to automate various tasks using "Macros". Macros consist of a list of conditions under which a list of actions will be performed. Examples and guides can be found in the wiki. Feel free to contribute! If you run...
obsproject.com