The carvings were too stylized to see if they depicted a single species in varying symbolic ways, or several. They might have depicted either the species themselves, or perhaps their mythological figures
A planet in the Delta Quadrant was said to have been inhabited by a certain people ten thousand years before the 24th century. By that time, only a few symbols burned into the rocks remained, as well as a path that was known to the current visitors to the planet, the Mikhal Travelers. However, the travelers knew little about the race except that they were spacefarers like them. (VOY: "Darkling")
Since so little is known about the race, their classification as humanoids is hypothetical.
The last three images are re-used footage from the 1997Paramount Pictures produced and Paul W.S. Anderson directed science fiction/horror film Event Horizon which were re-used to appear as violent thoughts of Tuvok. The screaming individual appeared in the beginning of the film as a vision to Sam Neill's character and was played by British stuntman Steen Young.  The burning individual was identified as "Edward Corrick" in the film and was credited as "Burning Man", played by actor Noah Huntley, who appeared twice in the film. The humiliated individual appeared in the first 30 minutes of the film, as the corpse drifting on the Event Horizon's bridge and discovered by Kathleen Quinlan's character.