So, the site is now online and you can check this problem live.
here is another picture with this white pixels: http://www.team-porzellanhandel24.de/category/portfolio/lexan-sus/
choose the second picture. always on the black parts aof the pictuere. in this case on the girl left and on the boy right (on his shoulders).
here you can see a strange case: http://www.team-porzellanhandel24.de/category/portfolio/matthias-anders/
choose the second picture. in the dark parts of his helmet there a the white pixel. but not by start. they appear just a moment after the picture-description is loaded.
so the pixels seem not to be in the image. if you turn of java, they don't appear.
in firefox everthing is ok.
how can I fix it?