This is a shot, from 2006, taken with a 6-megapixel APS Canon 300D with a Canon 28-300mm zoom at 300mm, at 1/800th, at f5.6 and ISO 200.  It’s been cropped to allow the full width of the frame, but with the distant plain, sky, and foreground cut away, so it’s actually about 4.3 megapixels’ worth of picture (3072 x 1413 pixels).

It’s shown here, reduced by about two-and-a-third times to fit this page, and with its filesize compressed from 6 megabytes to only 856 kilobytes so that it loads here quickly. 

It’s been mildly edited in the very simple Apple ‘iPhoto’ program as shown here, to the right:

end of this page

The glaring whites, or brightness, is reduced (..that’s the right-hand ‘Levels‘ slider..) and the edge contrast (..‘Definition’..) has been increased, and the Shadows have been lightened very slightly (..by about 17%).

That leaves just over 4 megapixels‘ worth of photo.

And here’s a 0.2 megapixels‘ worth of 100% crop from that:    

So this small crop (above) at 544 x 352 pixels is about 0.2 megapixels’ worth in total.  That’s ONE FIFTH OF A MEGAPIXEL.  But its SHARPNESS, or its detail, depend upon the quality of the LENS which was used to shoot it, as well as the processing algorithms used in the camera, and those used in any editing software which delivers the final image, and assumes a fast enough shutter speed - and / or extra stabilisation - to avoid any shake or blur.

But for 0.2 megapixels it looks pretty acceptable (..to me, anyway..) here on this web page.  Its quality isn’t dependent so much on its number of pixels - at least, not on a computer screen (a top-of-the-line 4K screen delivers only 8 megapixels maximum capability, so any greater pixel count than that just isn’t visible) as on the  quality of the original lens, the quality of the camera’s own conversion of different amounts of white light received on its Red, Green and Blue sensor photosites, into a human-comprehensible picture, oh, and plus the characteristics of any editing software which has been used.

Have a look at the 2 megapixel image, Picture F, six images down from the top on this page:  http://edituk.com/Cropped_from_28mm.html