but I have only one picture I want to be linked to the album. Is it possible to erase these pictures, because they appear as linked to the album in som music players? I want to get rid of them.
There is a transformation called Make the largest image "Front Cover" and remove the rest, by the end of the list (the 7th from the end in the documentation. If you want to decide for each song what image to keep (rather than the largest), that cannot currently be achieved with MP3 Diags.
If you still see several images in your music players, it's probably because you have image files in your directories. Again, MP3 Diags cannot help. It loads images from these files but it doesn't touch the files.