I finally managed to get the custom image into the Picture object of CR 
What I was doing wrong was calling the wrong crystal report (dohh), because I have more then one - its was my bad in the last day.
What I did, only there is a slight issue with the positioning of the image (for example: the Picture has dimensions width = 2000, height = 2000 (so 200x200 pixles), and I resize each image user want to use for the logo, but the image somehow it becomes bigger! Thats strange. Any Idea?
ok, this is what I did by the steeps:
1. read the image from db into byte[]
2. convert it to Image object
3. load (create) it one some hdd path + image name (i.e. "C:\myimage.jpg")
4. use path as object in the parameter
This is it, and it works.
The only thing is the image size. Do you have any idea how to salve it?
Big thanks to you Dell - you are the Man!