So first off I need to preface this by saying that I am in no way as good with Magic as most of the people who post on here. On my YouTube channel (shameless plug coming up) House Music All Night Long I try to incorporate the artwork for the release the tracks came from into the video. This is one of my latest uploads:
As you can see it has ended up somewhat pixelated on YouTube, which is a shame, but there's not much that I can do about it.
I also do videos for some of my mixes which is tricky because they are generally 60-70 mins long. If the visuals are any way graphically intense the video ends up far too large and looks awful on YouTube. This is the latest mix I uploaded to YouTube: