Android app: informing users that an image is clickable

I have an Android app. In its help section, there are some images that are clickable and if clicked user can see more information. And there are images that are not clickable.

Other than adding a text above or below the images that are clickable and explicitly mentioning that, what are the best ways to show that an image is clickable?

On the web, this can be done by hovering when the mouse goes over the image, but is there something similar on Android for mobile apps?