The first image depicts a cat who looks very confused at the sudden appearance of a bright green dot on the floor. The wavelength output of the laser is 532 nanometers so the cat is questioning why someone would create such a dot. (lol nerd joke)
The second cat is on a table next to a pineapple. Theoretically this is already a humourous situation but the point of the thread is to have text on the cat images (often in the form "im in/on ur _______, ______ ur ______") so I simply chose the most obvious.
The third cat is laying in a shoebox with his head hanging out the end, a position which looks rather uncomfortable. But if the shoebox had been larger the problem never would have arisen, hence his lamentation of the bed being insufficient in size.
The fourth image is of two cats, one of whom appears to have a choke hold on the other. One can assume that if the cat was to convey his intentions to the other cat prior to this event, he might reasonably say "I am planning to choke you", which can be shortened to "imma choke u" in accordance with image macro text guidelines.