I have the perception (but no sources to confirm or refute) that technological progress was fairly stagnant in Europe after the fall of the Roman Empire until the Renaissance.
One thing that has always struck me is the extent to which art regressed, antient Roman artists were capable of this (art in Pompeii) whereas a good chunk of Medieval art looks like this. Was technological development similarly affected?
As Tolkien said, "Go not to the elves for answers, for they will say both no and yes."
"Progress" is a tricky thing to define objectively. In the artistic example you give, the medieval picture is only a "regression" if your goal is realistic depiction, which was not a particularly medieval goal. Similarly, were we to look at architecture, we might see the medieval Gothic style as an "advance" from Romanesque construction. But we would do well to remember that the reason we call it "Gothic" is that Humanists in the Renaissance thought it looked hideous and barbaric.
With that major caveat in mind, what we have is a mixed bag. Medieval medicine continued to center around Galenic theory (2nd c. AD), but it's worth noting that Galen borrowed wholesale from Aristotle, so "medical technology" was "stagnant" for Rome, too. Architecture, we've seen. There were some changes in ship designs, and gross tonnages (probably) dropped before rising. Road quality dropped, but this is more the product of the organization of states. The quality and sophistication of book production rose greatly.
TL;DR: a mixed bag. Things changed, as they are wont to do. How we chose to divide that change into "good" and "bad" says more about us than it does about the subject at hand.
