Whatsapp Profile Pictures folder missing
WhatsApp no longer caches/stores the viewed profile pictures under /sdcard/WhatsApp/Profile Pictures/ directory, due many reasons, like this..Now, it's stored under its own app cache area in /data partition.

If you're rooted, then head over to the directory: /data/data/com.whatsapp/cache/Profile Pictures/.There, you'll find the cached profile pictures (that you have viewed).

If you're not rooted, as others have said, you need to explicitly save the profile picture from the WhatsApp app by clicking the pic, click again to enter full screen, click the 'Share' icon and press 'Save to Gallery'.

Now the saved profile picture can viewed in the directory: /sdcard/WhatsApp/Media/WhatsApp Profile Photos/