Confusion over megapixels vs. megabytes

It appears that every reply that claims to simplify this issue makes it more confusing. The stored file size is not important and can be ignored.

First, the megapixel value of the camera refers only to the number of active image areas on the electronic sensor. It has no relation to the resolution of the saved image. In fact, every digital camera image has a resolution, measured in pixels per inch, of 72ppi. What matters is that a sensor with a larger active area, 14-megapixels vs 3-megapixels for instance, captures more information resulting in a larger file size measured in megabytes.

What is most important is the concept in photography consistant in both the digital and traditional film world. That is, that the resolution or clarity of the original image increases as the printed copy is reduced in size. The 3-megapixel and 14-megapixel cameras will capture the same scene, but the 14-megapixel camera will produce a much better quality 16"x20" print simply because you are starting with more information making up the same scene.

And my 3.1-megapixel Nikon 995 produces an almost as good quality 24"x18" poster as my 6-megapixel Nikon D70s when printed on my HP130 Designjet.

Also, pixels per inch (ppi) is the resolution of a displayed image while dots per inch (dpi) refers to a printers resolution and the two are not the same.

Mega- is a prefix and is used to represent a power of 10^6. It is a fairly common SI units prefix. Thus you can have megabytes, mega-pixels, megatons (or mega-grams), and megawatts. The mega does not reply that the units are the same or even related (Ton is a unit of mass and watt is a unit of power). A pixel is a point and a Byte is a unit of storage.

Pixels is the amount of dots in your picture, the more dots the better and can be printed out larger.

Usually the more pixels, the more bytes in size. But darker pictures is usually smaller in size compare with colorful images. So even though both are set to 12MP, the dark picture (maybe indoor with low light) most prolly has 3mb in size compare with lighter picture (park in day time) which prolly is around 4mb.

I read -most of- the contributions, I liked several, but none of the ones I 5read mention pixel size.
I have a Panasonic (Lumix)point-and-shoot with 6megapixel, recently purchased a Nikon -for the brand-name and the 15x lens. They have the same size chip -really tiny- the difference is that Nikon stuffed more pixels in the same size chip, consequently the Nikon chips are smaller than the Lumix.
When processing the pic. Nikon also compresses it more than the Panasonic, thus the pic. is smaller in megabytes, although it presumably has twice as many pixels.
Since the Nikon has smaller pixels and higher compression, the pictures ae actually less sharp and the color are less vivid. So I went back to my Lumix, whic may have less pixels in the similar size chip, and with less compression the pictures are sharper and have better color reproduction.
In photography, some of the terms from negatives continue to be used, thus we have SLRs with 35mm size chips, APS-c size etc.
Of course the larger chips accommodate larger and/or more pixels, which give better pictures.
The main reason Nikon and Canon reduced the number of pixels in recent models was to have larger pixels, which translate to reduced "noise," better color and sharpness, and in some models dramatically increased light sensitivety. Some of the APS and full size (meaning 35mm equivalent) chips can take photos in very dark settings

Your megapixels are compressed into a file known as jpeg or jpg. This compresses a large image file into a smaller file on your SD card. That way you can take many more photos. If you set your camera to maximum resolution, you are getting what you want. Its all automatic for you.

Megapixel measures the picture quality, whilst megabytes measures the photos size on the hard drive/memory stick/cd.

Its a common error to make, but they are totally different.

remember it like this. a pixel is to do with picture quality whilst a byte is a measurement of binary code for storing data.