How to keep file quality?

[Utajeny5]

When i want resize image to format 800 x 800 px from 16 x 16 px what do i must do? I opened image that naturally is 16 x 16, and i just want to make it bigger and keep resolution. I tried to make minecraft dirt block to be in 800 x 800 format. 
And when i resize it to 800 x 800 this happens: 
What i need to do is to have same image in 16 x 16 and sam image in 800 x 800. Im sorry for this coplications but im starting with gimp.

[rich2005]

You have a 16x16 pix image where each pixel is one colour. You want to scale it to 800 x 800 without any mixing of the colours.

Use Image -> Scale Image set the size to 800 and interpolation to None 

   

[Utajeny5]

Thank you very very much