Does anybody have any idea how to make a visit to these far planets? Or why we would? Or when we could? Uranus, Neptune, Pluto images. Most are from NASA's Planetary Photo Journal arranged by planet and mission. Some are stock photo images.
photojournal.jpl.nasa.gov/

Uranus

PIA01360
Uranus, towards the planet's pole of rotation. "These two pictures of Uranus were compiled from images recorded by Voyager 2 on Jan. 10, 1986, when the NASA spacecraft was 18 million kilometers (11 million miles) from the planet. The blue-green appearance of Uranus results from methane in the atmosphere; this gas absorbs red wavelengths from the incoming sunlight, leaving the predominant bluish color seen here. The brownish color near the center of the planet could be explained as being caused by a thin haze concentrated over the pole -- perhaps the product of chemical reactions powered by ultraviolet light from the Sun. One such reaction produces acetylene from methane -- acetylene has been detected on Uranus by an Earth-orbiting spacecraft -- and further reactions involving acetylene are known to produce reddish-brown smog-like particles. A similar haze envelopes Saturn's moon Titan; ground-based observations have predicted such a haze in the polar regions of Uranus."

PIA02245
Neptune's blue-green atmosphere from Voyager2: Neptune's blue-green atmosphere is shown in greater detail than ever before by the Voyager 2 spacecraft as it rapidly approaches its encounter with the giant planet. This color image, produced from a distance of about l6 million kilometers, shows several complex and puzzling atmospheric features. The Great Dark Spot (GDS) seen at the center is about l3,000 km by 6,600 km in size -- as large along its longer dimension as the Earth. The bright, wispy "cirrus-type" clouds seen hovering in the vicinity of the GDS are higher in altitude than the dark material of unknown origin which defines its boundaries. A thin veil often fills part of the GDS interior, as seen on the image. The bright cloud at the southern (lower) edge of the GDS measures about l,000 km in its north-south extent. The small, bright cloud below the GDS, dubbed the "scooter," rotates faster than the GDS, gaining about 30 degrees eastward (toward the right) in longitude every rotation. Bright streaks of cloud at the latitude of the GDS, the small clouds overlying it, and a dimly visible dark protrusion at its western end are examples of dynamic weather patterns on Neptune, which can change significantly on timescales of one rotation (about l8 hours)

PIA00052
Neptune Great Dark Spot in High Resolution
This photograph shows the last face on view of the Great Dark Spot that Voyager will make with the narrow angle camera. The image was shuttered 45 hours before closest approach at a distance of 2.8 million kilometers (1.7 million miles). The smallest structures that can be seen are of an order of 50 kilometers (31 miles). The image shows feathery white clouds that overlie the boundary of the dark and light blue regions. The pinwheel (spiral) structure of both the dark boundary and the white cirrus suggest a storm system rotating counterclockwise. Periodic small scale patterns in the white cloud, possibly waves, are short lived and do not persist from one Neptunian rotation to the next.

PIA02210
This contrast enhanced color picture of Neptune was acquired by Voyager 2 at a range of 14.8 million kilometers (9.2 million miles) on August 14, 1989. As Voyager 2 approached Neptune, rapidly increasing image resolution is revealed striking new details in the planet's atmosphere, and this picture shows features as small as a few hundred kilometers in extent. Bright, wispy "cirrus type" clouds are seen overlying the Great Dark Spot (GDS) at its southern (lower) margin and over its northwest (upper left) boundary.

PIA01492
The images of Neptune were taken at a range of 4.4 million miles from the planet, 4 days and 20 hours before closest approach. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb the fast moving bright feature called Scooter and the little dark spot are visible.

PIA01542
Neptune, "a planet whose blustery weather -- monster storms and equatorial winds of 900 miles per hour -- bewilders scientists. The weather on Neptune, the eighth planet from the sun, is an enigma to begin with. The mechanism that drives its near-supersonic winds and giant storms has yet to be discerned. On Earth, weather is driven by energy from the sun as it heats the atmosphere and oceans. On Neptune, the sun is 900 times dimmer and scientists have yet to understand how Neptune's weather-generating machinery can be so efficient. 'It's an efficient weather machine compared to Earth,' said Lawrence A. Sromovsky. 'It seems to run on almost no energy.' "

Pluto

Pluto typically is called the double planet because Charon is half the diameter of Pluto (our Moon is one-quarter the diameter of Earth). Though Pluto was discovered in 1930, Charon wasn't detected until 1978. That is because the moon is so close to Pluto that the two worlds are typically blurred together when viewed through ground-based telescopes. (If our moon were as close to Earth, it would be as big in the night sky as an apple held at arm's length). The two worlds are 12,200 miles apart (19,640 kilometers).

PIA00827
Hubble Portrait of the 'Double Planet' Pluto & Charon
The image was taken by the European Space Agency's Faint Object Camera on February 21, 1994 when the planet was 2.6 billion miles (4.4 billion kilometers) from Earth; or nearly 30 times the separation between Earth and the sun.

PIA00825
"Discovered in 1930, Pluto has always appeared as nothing more than a dot of light in even the largest earth-based telescopes because Pluto's disk is much smaller than can be resolved from beneath the Earth's turbulent atmosphere. Pluto is 2/3 the size of Earth's Moon but 12,000 times farther away. The two smaller inset pictures at the top are actual images from Hubble. North is up. Each square pixel (picture element) is more than 100 miles across. The larger images (bottom) are from a global map constructed through computer image processing performed on the Hubble data. The tile pattern is an artifact of the image enhancement technique."

PIA00826
"Map of Pluto's Surface, The brightness variations in this map may be due to topographic features such as basins and fresh impact craters. However, most of the surface features unveiled by Hubble are likely produced by the complex distribution of frosts that migrate across Pluto's surface with its orbital and seasonal cycles. Names may later be proposed for some of the larger regions."

Voyager visited these four planets. Jupiter, Saturn, Uranus, Neptune. Pluto was skipped.