The only question is whether they'd receive the images before the missiles launch and are detected by radar and the like. Presumably it doesn't take that long to launch a missile after opening such silos given the need to be able to launch missiles within about 30-45 minutes after the enemy launches theirs, since any missile still in its silo when a hostile nuke hits will be going nowhere.
I imagine that for a sufficient exchange, something of a theme of "oh look, their hatch is open" would be a recurring buzz amongst the analysts and/or the image-processing algorithms tasked to review the download from the small but significant cloud of top-down imagers that are whizzing around with this very specific job amongst their priority lists. Eyebrows would be raised fairly quickly as the duty officer realises that there's a lot of "possible spring-cleaning" being initiated in the last few minutes and more information would quickly be sought by specifically checking other indicative sites, in leiu of any other routine targets for review that are now considered secondary and can wait a bit...
For a limited-launch situation, no doubt the activities can be planned around known coverage-gaps (knowing where milsats are over, at any given moment, although perhaps with the assumption that orientation to capture oblique views is rarer) and then it'd be the wide-angled detectors primed to pinpoint the thermal blooms of launch-stages that'll raise eyebrows and not a little sweat. Those and the radar-systems that can quickly use artificial-aperture techniques once certain detection fingerprints have crossed thresholds in a general low-power sweep. (I'm guessing at how they work, but in an educated manner.) But for anything whose
results are fairly likely to provoke a proportionately massive response, they might consider it as well to be hanged for a sheep as a lamb.
Thus I can't see it being anything other than just the same long-range conventionally-fipped attacks as seen landing all the way over to the west of Ukraine (whoops, was that a busy railway station we hit? We were sure it was the Nazi Stormtrooper HQ)
or go for the major play to end all major plays and Press The Big Red Button (and let the devil tak the hindemost, ye ken?)... I can't see any scope for anything tactical.
Possibly something like laying a demolition-sized warhead down upon the Azovstal plant complex (though, again, the complication of going non-conventional is clearly crossing a line), but they don't need ICBMs/hypersonic-FOBS to do that, given they're already milling around the outside and there's no benefit to risking a long-range miss (or the problems of whether/how much to take the cordon-manning troops and move them away a bit) when they could probably just use a forklift truck or three with a unit guarding the delivery/ies then withdrawing after lighting the metaphorically blue touchpaper...
Totally thin-air supposition on my part, of course. What's running through the minds of the coordinators and contingency planners, let alone their boss, is beyond my pay-grade. There'll be far more informed people than I worrying (or not) about how far this sort of thing will go. But my assessment is that it'll be very obvious if the balloon ever goes up, and long enough before it falls back down again for a whole lotta military/diplomatic/etc response to be initiated to try to halt it all. If it's a very committed bluff, the latter could be what diffuses/defuses it. If it aint, then good luck with the Iron Shield-type multinational system in winnowing everything down, as we almost simultaneously possibly get to see how good
their defences operate. Nasty business, either way.