I see many nice pix etc. @ Google reader Play.
Is there a way I can share my own pix / vids / stuff so it should publicly be visible there too?
As long as your content is publicly available on the internet it is theoritically eligible to be included in reader play. According to the documentation the criteria for making it into reader play is whether your content is being shared, reposted, linked to by others. It uses the same principles that the recommended items feeds use to get content.