Well nevermind, i found out by myself "

1) There is a dll.file that is to be "hacked" by a software, and then the image can be exported as a bmp file to photohop.

2) The image saved in photoshop must have the same pixel size AND be saved as a 16 bit bmp image (not 24bit).

3) Then import the bmp image back to mayastartupimage.xmp (if i remember correctly, you cant miss it).

And voila!

Forgive my blasphemical action here.