Counting pixels in a block of text to determine information density doesn’t sound like a very robust method to me. You could get very different results depending on the font you use to render the text.
Lithuanian has quite a heavy use of diacritic signs, but it seems to pack more information than the others. And other languages with similar diacritic signs are not close to it.
Although the sensitivity to different fonts and details is real, we can draw some interesting conclusions from this Sunday exercise.
In this test it'll comfortably beat out any other language.
See: https://fontstruct.com/fontstructions/show/325977/4x3_pixel