If you mean so that you can zoom in and see the same quality as you did when it was 2010 x 1080, you can't, this is impossible.
Imagine a 3x3 grid with the following (r=red, g=green, b=blue):
If you then want to change it to a 2x2, it will do something like this (b=blue, y=yellow, p=purple):
Then, when you try to stretch it again, it will try to restore the colors, fill the gaps and work out what should be in certain places.
It is nearly always the case that the quality loss isn't that visible when you zoom in only slightly, but it is always the case, and if you are going from 2010x1080 to 338x450, you certainly will see it.
Also, if you were simply changing the size from 2010x1080 to 338x450, it is possible that you were distorting the aspect ratio which is a completely different issue.
You may want to look in to cropping the images instead, basically (image manipulation software dependent), drag a square around the parts of the image you want then just keep that part.
Also, when you have a selection or image you want to shrink, some utilities allow you to lock ratio, if your software doesn't, just remember to divide by the same ammount, for example a half size 2010x1080 would be 1005x540.