Camera

Megapixel 
Megapixel is one million pixels (1000000 pixels) short form. Pixel in an image file of the unit; (With existing image data) in a single point. A megapixel image can be  any shape. It is actually (eg 1000 x 1000, 1200 x 834, etc.) (vertical) (horizontal) and height of the image's width is calculated from multiplying. More megapixels means larger and more detailed images.
Camera Pixel
Camera Pixel or, Camera Resolution is the maximum image size that can be captured by a camera. It is counted as the same way the Megapixel counted (mentioned above).
LED Flash
LED Flashes are flashes made of LED (Light Emitting Diode) lights. Majority of the camera phones uses it. It is less power consuming and flash power is comparatively lower than Xenon Flash. But, now a day, market’s top Smartphone’s LED flashes have been improved a lot. LED Flashes can be used as video light (lighting while capturing video).
Face detection

Face detection is a computer technology that catch the locations and sizes of human faces in unrestricted (digital) images. It find out facial features and ignores anything else, Like as buildings, trees and bodies. Localization of face detection can be considered as a general case. In the face localization, the task of a known number of faces (usually one) is to find the location and size. In face detection, one does not have this additional information.
Geo tagging

Geo tagging such a geo tagged picture or video, websites, SMS messages, QR codes geographical identification metadata to various media in the process of adding or RSS feeds and is a form of geospatial metadata. This data usually build of latitude and longitude coordinates, though they can also include altitude, bearing, distance, accuracy data, and place names.
Geo tagging can help users find a wide variety of location-specific information. For example, one can find images taken near a given location by entering latitude and longitude coordinates into a suitable image search engine. Geo tagging-enabled information services can also potentially location-based news, websites, or other resources that can be used to find. Geo tagging can tell users the location of the content of a given picture or other media or the point of view, and conversely on some media platforms show media relevant to a given location.