primary photo does not display in blog readers

Hi! In blog readers such as bloglovin’ and feedly, the primary photo I set in the Reddle theme does not show in the summary. It shows no photo if there is only a primary photo, and another photo instead of the primary photo if there is one. Since my blog is about cooking, often if there is a second photo, it is not of the dish but of an ingredient or method, which is not what I want as the primary photo. Help! thanks!