Everyone loves a good photo, and it's (perhaps inevitably) the Kodak moments that cause the 'wows' amongst us amateurs. Any data from unmanned missions is incredibly valuable and hard-fought but it's the imagery perhaps above all else which underpins most of the missions.

These images we're privileged to share are achieved by the passion and ingenuity of those involved in the missions and the collaboration of perhaps dozens (hundreds?) of people. To achieve some of the images we've seen on recent space missions there is a requirement for:

Exquisite knowledge of the ephemeris of a given target, plus it's size and albedo
Very precise knowledge of the spacecraft trajectory and velocity
Propulsion/attitude expertise
Camera filter, exposure/light levels, spot-on pointing, motion compensation
On-board software (sometimes updated on the fly)
Data storage capacity/playback timing
DSN availability

Following the recent phenomenally impressive imaging of Ganymede during the flyby by Juno, I thought it would be good to remind ourselves of other imaging triumphs over the last ~50 years, so here are a few off the top of my head:

Voyager 2 at Miranda - compensating for a stuck scan platform by slewing the spacecraft using thrusters to compensate for motion blur and light levels the camera wasn't designed for
Hi-rise - Phoenix under parachute at Heimdall (I can't imagine the number-crunching involved in getting that to work)
Cassini - Methone at Saturn - these snowballs are a bit unpredictable in their orbits
Juno at Ganymede - spin rate, speed of flyby
New Horizons at Arrokoth - the KBO was discovered on the way there, speed of flyby and the low light-levels. Upgraded software and best-guess pointing
Hi-rise capturing Comet ISON at Mars

I'm sure there are a raft of others......

I always liked the pictures of Mars Odyssey and Mars Express orbiters photographed by Mars Global Surveyor in 2005. A spacecraft in orbit around mars taking pictures of other spacecraft in orbit around mars. The pics of Mars Odyssey from 90km are striking in their clarity. I bet the Mars Odyssey folk never expected to see it again post launch!

https://www.nasa.gov/vision/universe/solars...mgs-images.html

I would add the Huygens probe photo from the surface of Titan—amazing!

Pioneer 10 and 11 took images with their Imaging Photopolarimeter scanning over the target as the spacecraft spun, only imaging 0.03° per scan, and needing to perform red and blue separately. It's remarkable that we saw such good photos processed with that intricate approach and the limited computational power of those times.

The LRO image taken during an impact on the camera is just too cool to forget; even though it was completely happenstance:
http://lroc.sese.asu.edu/posts/973

How about the moment Linda Morabito turned up the gain on a photo of Io from Voyager, looking for navigation stars, and saw volcanic plumes!