I'm very happy but I found a new bug.
This is again a bug related to pictures with alpha but it happens with all formats with alpha. Not only TGA.
This bug happen only when the picture is bigger then the screen. Xnview show the picture scaled so that it fits the screen and this cause the bug!
If I zoom in or zoom out the picture, I see it perfectly.
I want to add another thing. This bug is visible only when Xnview's window is big as the screen (maximized)! If the Xnview's window is a floating window the bug disappears.
I show you the bug:
This is what I see when I double click a picture that has alpha and is scaled to fit the xnview canvas. Do you see all those white dots?

If now I zoom in or zoom out the the dots disappear. This image is at 100% here

If I open a picture smaller then the previous there is no bugs. In this picture I opened a scaled version of the previous image. See? No dots because it opens at 100% zoom

I add that the dots appear also if I click "M" to see the alpha of the picture. In this image the alpha is white. Do you see the black dots?

I attach a copy of the picture used in these example.
You can download it here:
https://www.mediafire.com/file/pw2gov3u ... g_dots.rar