It is a 800x560 picture file. Whatever image you use must be 'converted' to a true bik animation (or static), compressed with Rad-Tools (at 30fps & most probably above 800,000 ratio) and then... it has to be loaded straight from the mod folder by using the same default name.
That new one would replace the terror star.
In that case, the dxpack file editing is unnecessary.
Actually, i'm quite busy with my own stuff (CoSH & X-Worlds) and can't do everything for everyone here. I gave race portraits to AF for his Fed&Emp mod... in exchange for his work on some X-Worlds ships & fleets. I made the altered *Improvements* & Logo for MrKorx's Asa custom race since he could provide me (and offered it in fact!) with precious info & tricks about creating a working fleet - again, for X-Worlds.
So, all i can say is good luck with ANE (btw, you should start a new thread for it if you're serious about this whole project of yours) since this one is about AFRonin's development things & discussions!
OFF-topic over, AFAIC.