Does increasing the number pixels in an image by resizing tools produce a better quality image?

Question

After read this article: PPI vs. DPI: what’s the difference?
There's this sentence:

1. Does it makes an image better quality by increasing its X and Y pixels?
2. If I resize an image(A) by doubling its X and Y pixels and save it as a new image(B), afterwards I resize this new image(B) back to the original X Y pixels (C), is image C the exact same quality as A?

Answer 1

Just increasing pixels will not improve quality.

You might want to check how Adobe using mathematical functions (Smoothing etc.) when resizing images to increase resolution without creating pixelation, etc.

Answer 2

Increasing the Image size just by doubling the pixels, doesn't improve the image quality. If you want to use a tool like photoshop and improve the quality, then there should be functions available. But if you want to do it programatically then you should use filtering (to remove noise) and improve the contrast and brightness.