NASA recently published this photo taken by Juno, at a distance of about 700,000kms from Jupiter:
The overall quality (very grainy around the darker regions, a bit washed-out in the brighter areas, and not the greatest dynamic range even in areas that are properly exposed) and resolution of this photo seems to compare poorly against images taken from ground-based telescopes:
...and also from the images that we can get using Hubble:
...both of which would have been shot at distances of closer to 600 million kms from Jupiter.
I understand Juno will get even closer to Jupiter than it currently is, but at the moment it's nearly 1000x closer to Jupiter than Hubble/Earth-based observatories and returning images that, at best, appear to be on par with what we can accomplish using terrestrial telescopes.
Is there a reason for this (like maybe the images released were shot in a low-resolution/low-bandwidth mode that doesn't actually use the camera's full capabilities), and what sort of improvements in the image quality can be expected as Juno reaches its closest orbital altitude? If the image quality can't be expected to drastically improve, was there a reason for not equipping the mission with better imaging technology that can at least clearly eclipse what we can attain by using Earth-local resources?