ok, I'll try but I have to do it in English because my russian is very bad.
So what does 'prozrachnij fon' means?
That means that images contain 'alpha channel'. Alpha channel tells where the image is 'prozrachnij'.
JPEG files don't have alpha channel. And cannot have.
That's why u need to export images not as jpegs but as TIFF (which has alpha channel).
So let's make an example for rendering in Poser with alpha channel.
start poser. Go to "Animation" (between "render" and "window" ) ). Then select "Make movie". On "sequence type" make "Image Files". Then press ok. On "Save As" select "Save As Type" to be TIFF. Press "Save". And u have TIFF sequence with alpha channel.