VGA vs. Megapixel
Because VGA covers only 640 x 480 pixels, the picture is small in size. Therefore, when it is enlarged or stretched, it is pixelated. The image can result to poor quality. Compared to other resolutions, VGA can appear to be chunky and choppy. With the advancement of technology, color palettes have become bigger and have gained more colors, which VGA lacks. As of now, the highest color palette is 24- bit RGB, which has 16, 777,216 colors. This is equivalent to the thrice of VGA's 256- color palette.
In size, it is very much obvious that megapixel is way bigger than VGA. The latter has only 307,200 pixels, while the former translates to "million" pixels. Most, if not all, modern cameras have megapixels that range from 3 to 12, or even higher. Also, cameras that are measured through megapixels are more capable of producing clearer and bigger pictures and excellent quality. VGA- quality is much better for mobile phones and Multimedia Messaging Service (MMS). Whereas, megapixel are viewed better on the computer. However, when it comes to sending pictures wirelessly, it is better to use the VGA as it is easier, lighter, cheaper, and takes shorter time to transfer.
You may also want to read about DVI vs. VGA.