This repository illustrates that the dpi settings of graphics are irrelevant if they are embedded in a html document and viewed on a screen. They do get printed differently however if the printing application is capable to detect the dpi setting.
The html document in this repository has two png images embedded.
Both images show the same black circle, both are 30x30 px in resolution and both are 347 bytes in file size.
The first one however has the dot density set to 300 dpi and the second one has it set to 10 dpi.