Reduce quality of imported photos only

Hi, we have ‘jpeg_quality’ filter set for 100 because we don’t want to have blurry product images, but we want to have imported review photos with much lower quality – around 40%. Can you tell how can we reduce only imported images quality on fly to this amount? Actually the smartphone cameras like to save photos in png format, so we expect most of the organic review photos to have in this format. Can you please tell if is there a solution that would work for jpeg and png?