You're confusing me - you used this phrase: ***accurate preview instead of a flat white
***indicating you think that an accurate preview has to be stored somewhere, whereas a flat white image does not or can be stored in a different amount of memory. If not that, then what were you getting at regarding the contents of the preview?

I think maybe you need to restate your basic point since I don't seem to be responding to it.
 
Here's what I assumed your basic points were:

**For video memory I know fairly certainly that, if the color depth and resolution is the same, then the video memory used will be the same.  **
If your talking about hardware accelerated pose-room preview, then as I just pointed out, that's wrong. if you use images in your shader, then those images have to be copied into the hardware as well to do hardware-generated pose-room previews. 

If your talking about software generated pose-room preview, then that's wrong because you qualified it with "if the color depth and resolution is the same" - video memory use is not in any way changed by software generated pose-room preview, color depth and resolution have nothing to do with it.

If your talking about rendering, then that's wrong, because again the hardware is not involved.

If your talking about mat-room previews that's wrong because those are not hardware accelerated.

**For system memory I think it'll actually be a little bigger for the procedurally-generated bitmap, **
And that's wrong as I've shown you because procedural textures algorithms are smaller than images in all cases. Even a 100 by 100 bitmap is bigger than the data needed to represent a procedural shader. This is true regardless of whether the procedure is running in your PC or on your graphics card.

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)