There are two "usual" ways to detect a black hole:
If it is part of a binary system (two stars closely rotating around each other) and dragging matter from the other star into an accretion disk, that disk will heat up. Energy distribution will tell us whether the accreting object is indeed a black hole or a neutron star instead. This is primarily visible in X-ray, so not an answer to your question.
If the black hole has a mass of 100.000 to millions of times that of the sun (supermassive black hole), it will sit in the centre of a galaxy, and sometimes accrete matter. This is mostly visible in Radio, and again in X-ray. Still not an answer.
So, how can we detect a black hole in the optical? Best chance is an indirect detection, like in the images you linked above. The one with the distorted stars in the background is not "just fantasy", but a simulation based on our understanding of gravity. The problem when we try to see this is scale, and hence resolution. The event horizon of a stellar mass black hole is on the order of a few kilometers.
Let's replace our sun by a black hole. At a distance of $1.5\cdot10^8$km, with a black hole diameter of 6km, we'd see it occupying an angle of
\begin{equation}
\alpha = \tan{\left(\frac{6}{1.5\cdot10^8}\right)} = \frac{6}{1.5\cdot10^8} = 2.3^{\circ}\cdot10^{-6} = 8''.3 \cdot 10^{-3}\,.
\end{equation}
So a solar mass black hole at the position of the sun would be 8 milli-arcseconds (mas) in size. A single 8m Telescope at the VLT has a resolution of 50mas. If we consider that the gravitational lensing effect takes place on scales larger than the Schwarzschild radius, it could just manage to see this effect. (The theoretical resolution limit for an 8m telescope at 500nm wavelength is $1.22 \lambda / d = 15$mas.)
For real black holes at distances of 10s or 100s of lightyears, you would need a truly gigantic telescope.
Next option, again with gravitational lensing: The microlensing effect causes a background star to be temporarily magnified - it shines brighter for short period of time. A black hole passing in the foreground can cause this, and it is an optical observation, but it is very difficult to know that the lens was indeed a black hole and not some star or other compact object.
Last option, Hawking radiation: Hawking postulated that black holes might emit radiation inversely proportional to their size. For small enough black holes, this is a runaway process - they emit more as they get smaller, and because the emission causes them to shrink, they emit yet more again. Since Hawking radiation has a black body spectrum, the maximum of this emission will lie in the visible range for a brief period of time before going into UV, X-ray, and gamma radiation. The problem here is that no one has observed it yet, and you'd need a fairly small (but not too small) black hole close by. Also, you might get killed as the radiation gets harder.
To your questions:
- Possible, but probably not. You would need to get very close, but not close enough to get killed by tidal forces. Or you'd need to be able to identify a microlens as a black hole by some means other than lensing.
- Either lensing effects (see above), or a brief flash going from red to blue (probably too short to observe).
- These black holes would be mostly visible by the absence of other particles. You'd get less elementary particles than you would expect for the reaction,some energy and some momentum would be missing, and there would be characteristic gamma radiation. However, for CERN to announce this, this would have to have happened often enough to not be a statistical fluke (this turned out to not be a detection after all.)
