The topic above is misleading. I do not think pixel art as we know it and it formulated in early 1980's was informed of how the Italian masters worked. I do however think important artistic parallels can be drawn between the techniques of artists separated by 15 centures of history, and that in itself is a very useful lesson. It shows us that good artistic practices are independent of 'pixel art tech' as we have defined them here, and how also common faults we see in pixel art are seen in their art as well which tells us again that they are more an aspect of general draftsmanship than they are pixel-art specific errors. Let's look at some scans I've done from details from various religious sites in Ravenna:

First of all this is an important picture to show the actual scale of a lot of these images and the 'intended res' they should be viewed at. Also it's worthwhile so we can appreciate that they didn't have no clone tool or anything and everything is made bit by bit, not even floodfill! (I guess this shields them from allegations of being NPA

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Let's look at this amazing detail. Note the expressionistic color palette... hue shifting towards blue on some leaves. Check out the colored outlines around the fruit. Look at the highlights on the rims of the basket. Solid black outlines on the basket to separate it from the foliage too. As usual in Byzantine art, strong and saturated dark colors are the norm, seeming to glow with an inwards - divine - radiance. Look at the artist trying to reconcyle the religious dictum of how things should be shaded (blanket-shaded was mandatory! inwards glow!) and still give it a few naturalist highlights like in the fruit or rims.

Let's look at this proto-Mondrian painting. Check the palette vibrance. On decorative strips is where a lot of these religious artists got the chance to express something more than they were told. This is very easy to repixel too. Look how every stripe practically hue-shifts.

Sorry for book shine, I didn't want to slaughter it. Here is a great example of the Byzantine 'inwards glow' on the faces and clothes of the angels. Look at the gold background, that is Heaven.

Say hello to emperor Justinian. Not a very pleasant fellow, hm? Brilliant man, though. This is an amazing piece of art in my opinion. Check various face shades, some more red, some more brown. Imagine looking at this above you in the ceiling suspended in the Heavens, enshrined in golden grace, judging you with that stare. The point of religious art is to impress upon the viewer their punyness as in relation to the divine. And Justinian felt it useful to be thought of as divine. Job well done, then.

A bit of humour then! HAY GUYS WHAT'S UP. I love this bird. I love the vibrant colors I love the amazingly pronounced hue shifts in its feathers, I love the black outline (the fore leg breaking out of) and generally I love everything about this. I might repixel a copy of this to use as an avatar later!

And also here's some MoSaic Paint pixel art!

Here's a mockup. Useful to see how the elements look in relation and more from afar. Check out how the white bits around the pieces don't show so much but make everything appear a bit glowy.
So, feel free to post more mosaic art, discuss it or even repixel bits and pieces in our modern tech and see how they'd look!