I'm assuming there is nothing needed here from the Growth team beyond the work that has been done in T336358: Make the growthimagesuggestiondata API available on wikis which have GrowthExperiments enabled but image recommendations disabled, please let me know if that's incorrect.

In T336419#8883387, @Tgr wrote:

I'm assuming there is nothing needed here from the Growth team beyond the work that has been done in T336358: Make the growthimagesuggestiondata API available on wikis which have GrowthExperiments enabled but image recommendations disabled, please let me know if that's incorrect.

@Tgr Yep, everything looks good, but just one tiny question:
On a wiki where image recommendations are not enabled, what's the best way to get a list of candidate articles? I don't believe generator=growthtasks will work; In lieu of that, we could always resort to generator=random and hope for a few hits, but I want to make sure there isn't something more efficient.

action=query&list=search (or generator=search) with the search query hasrecommendation:image (plus whatever else you want - we add articletopic:... if the user selects a topic, and set the sorting of results to random).

Excellent - thanks for all your help.