Qasr mosaic leopard and VMS Leo/August image

[Sam G]

This is the reason why I don't like to build a theory just on images, all the more, on one image. No image gives 100% proof of an assumption. 
In the present case, no image from mosaics or manuscripts fits entirely, and I find it natural. It is difficult to say, which example is better. 

It seems to me that the most precise matches are coming from these old mosaics, despite the fact that there are vastly more surviving medieval manuscripts than mosaics, and of course we are only looking at mosaics in the first place because there are basically no surviving ancient books (which is where the best comparisons would almost certainly be found).  So I think that's a strong indication that these similarities are not coincidental.  Based purely on numbers, we would expect all the best matches to be in medieval manuscripts.

My first point (I hope, it is clear):
I don't see big difference between these: lion, tiger and panther below.

I don't see much stylistic similarity with the VMS image at all.  Or do you mean that those three animals resemble each other (but not the VMS image)?  

My second point:
If this image of Leo relates to ancient Greek or Assyrian and so on depictions/ mosaics/ zodiacs, how it relates to the whole VMs Zodiac, including the Sagittarius-crossbowman and the Scorpio-lizard? Does it relate to this Zodiac at all?

That's a good question.  I don't know exactly how the zodiac sequence we see in the VMS was produced.  I think analyzing the individual images in detail is the best way to figure that out.  As far as the other images, I haven't seen any strong parallels for the Scorpio image (which looks more like a monkey than a lizard to me, though I'm not saying that's what it is).  I suspect (but am not certain) that Sagittarius was originally a conventional archer who got a clothing update, like all other clothed human figures in the VMS, when this particular copy was made, and that update included changing his bow to a crossbow.
 

My third point:
Why can it be a transformed medieval Griffin, since You are not allowed to view links. Register or Login to view. presented in medieval bestiaries as a separate beast, still with the head and wings of an eagle.

Because it's a more precise match for the mosaic Griffin, especially in terms of the beak shape but also in terms of the ears.  Actually, other than in those precise details it doesn't look like a griffin at all, especially the more conventional eagle-headed kind.

My fourth point (last, not least):
The Leo of the VMs Zodiac has a mane, but it is too thin and obscure. I made a contrast of this fragment, so this detail must be visible a little.

I have trouble seeing it.  Maybe there are some lines here and there but I don't see an attempt at depicting a mane.