Let me try :-)

On the image below there are 2 squares. I don't know how big they look like on your screen, so let's say you have them on paper and each has side of 1 inch. The square on the left has less details than the one on the right. In other words the left square has less (lower?) frequency content than the right one. For the left square it is enough to sample it with rate of 2 dots per inch to perfectly capture it and then reproduce. For the right square you need to sample it with higher frequency of 24 dots per inch.

So for the left sqquare you get 4 samples (pixels) and 2 DPI sampling rate associated with it. Now you can upsample it by duplicating the samples a few times and associating 24 DPI sampling rate with it. If you open those 2 images in some viewer that is DPI-aware then they will look exactly the same.

The above is the equivalent of upsampling an audio from let's say 8 kHz to 96 kHz. I can see 2 reasons why it may be hard to see why they are equivalent:

- It may be hard to switch thinking from "samples per second" to "samples per inch".
- In contrast to audio, where every audio player is aware of sampling rate, most of the image viewers are not. I guess that's mostly because the viewing screen has fixed DPI density.

In audio, 8'000 samples at 8 kHz will play for 1 second and after resampling to 96 kHz the resulting 96'000 samples will still play for 1 second, because the audio card will switch its output frequency.

In image, 96x96 samples at 96 DPI will show as 1 inch x 1 inch square but after resampling to 192 DPI, instead of still showing as 1 inch x 1 inch, the resulting 192x192 samples will show as 2 inch x 2 inch because the screen can't switch its density.

As a practical example, the attached
2x2.png
(5.37 KB 2x2):

is 2x2 image at 2 DPI:

]$ identify -units PixelsPerInch -format 'number of samples: %w x %h\nsampling rate: %x dpi x %y dpi\n' 2x2.png

number of samples: 2 x 2

sampling rate: 2.0099999999999997868 dpi x 2.0099999999999997868 dpi

We can resample it to 200 DPI, either with ImageMagick:

]$ convert -units PixelsPerInch 2x2.png -filter point -resample 200 200x200.png

or with Gimp:

and we get 200x200 image at 200 DPI:

]$ identify -units PixelsPerInch -format 'number of samples: %w x %h\nsampling rate: %x dpi x %y dpi\n' 200x200.png

number of samples: 200 x 200

sampling rate: 200 dpi x 200 dpi

The one DPI-aware program that I know of is LibreOffice Writer. I suspect it will work the same in MS Word too. When we insert both 2x2.png and 200x200.png, they will look the same: