User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

I attached 2 test files. They are very simple.
SVG-file: there are 2 circles, and the second one disappears when width is less than 100px.
HTML-file: the same SVG-file is used twice - as IMG and as background.

Actual results:

Let's try to resize the browser window. If your display has a regular pixel density (scales in Windows and in Firefox are 100%), then it works normally.
But if your display is HD/retina or you have changed the viewport scale, then media query breakpoint is triggered at different times!
In Chrome it works well.

Expected results:

It seems to me that the background is working correctly (breakpoint in css-pixels), but the IMG does not (breakpoint in physical pixels).