What is actually the downsampling of 2 mean?
If I have an image size of 256x256x170 and if I downsample it by a factor of 2, it will result in an image of size 128x128x85?
Yes, that is correct.
Similarly, upsampling or resampling is the opposite interpolation method to original size 256x256x170?
Yes, correct result again. Resampling is a more general term ...