I've tried those but they don't change the naval/air units size:

Yes, it is. I restarted the game and now I see the image so maybe it was some temporary glitch on my system.

I noticed that sometimes the image in the top-right corner is not displayed, even though an unit has an image visible in DB viewer. Is this a bug maybe? I am on a Steam version 1.08.1674

I came back to playing Command after a long brake and I really struggle with unit icon readability. Regardless of how I zoom the map, the icons' size stays the same. Also, they are often largely obscured by the traingle sub-icon. Quick example is Surface Tutorial 1.2 (open the images in a new tab ...