What I would personally do is split each of those lines (it has been WAY too long since I played music, I forget all the terminology!!! hahaha) into their own separate SVGs/PNGs, instead of having an image of an entire page.
This way you could upload much higher resolution images, and not bump up against much of this "pixel size limit". But what do I know!
Side Note: Is this book also in blackletter font?
