Here are some leaked pictures of HTC Butterfly S. Not a surprise, it follows the good features of HTC One, like having the speakers on the front with Boomsound. No information on the specs but we can suspect an UltraPixel camera to accompany this device.
If you look carefully, the UI (User Interface) has the similar look of HTC (ie. HTC Blinkfeed). Here is another picture.
Based on the old Butterfly, it has water-resistant feature. Not sure if this Butterfly S has or not.