Difference between resizing an image and quantization of an image?

Hi there, I would like to check the difference between resizing an image and quantization of an image? From my understanding,the quantization reduces the number of distinct colors in an image while visually preserving the original image. But resizing by nearest-neighbor interpolation method allows me to achieve the same result while reducing the quality of the image(reduced pixel). If my ultimate goal is to reduce the memory consumption and processing time then which method should i consider for a color based image retrieval system ?

Answer 1

[Elad]

1. If you resize your image you reduce the number of pixels. so, if each pixels has 256 x 256 x 256 options, and you resize to 500 pixels you have : 256 x 256 x 256 x 500

2. If you use quantization the number of pixels remain, but you reduce the number of "colors", so if you started with let say 1000 pixels and reduced to 16 colors, you have 16 x 16 x 16 x 1000