You'll need to adjust your privacy settings for that photo and/or gallery to enable right click capability. Copy the link shortcut and paste it into your post here. You can always go back and disable right click capability after you post here to prevent others from downloading from 500px. Same goes for your SmugMug account. HTH.
I was able to view on SmugMug, not 500 Px. Loved the play between light, fog & nature. Please be aware that a large number of FM'ers will not go off-site to view images. You need image upload for FM. Jim