In heavens (there are many) beings are is rewarded for past good deeds.  Life there is a continual round of pleasure and enjoyment, with no suffering, anxiety, or unfulfilled desires until the moment one is about to be reborn in another realm.  And this is one of the problems—heavenly lifespans are extremely long (e.g., 30,000 years), but not eternal, and so one inevitably gets born somewhere else.  Rebirth in heaven also requires “spending” an enormous amount of religious merit, and heavenly life is so carefree that people ignore religious life and so make no efforts to gain more.  For these reasons, religious texts discourage seeking birth in heaven

The heavens are conceived as pleasant places, and this picture shows a lush garden and comfortable pavilions.  The resident Buddha holds a musical instrument.

Indian cosmology imagines many different kinds of superhuman beings.  Whereas devas (“gods”) dwell in the heavenly realms and are basically benevolent, asuras (“not-gods”) are opposed to the devas and in continual struggle with them.  Asuras are powerful but amoral beings primarily driven by envy and greed for power; these same qualities can bring them into conflict with human beings.  All of these qualities make birth in this realm undesirable.   

This picture shows images of conflict in the upper part (the asuras are generally seen as quarrelsome, so they fight with each other as well as the gods).  The resident Buddha holds a sword, which in Buddhist imagery stands for the wisdom that cuts through and removes ignorance.   

Animal birth is seen as the result of past sins, which one expiates through suffering (being hunted, worked, driven, slaughtered, etc.), sometimes for thousands of consecutive births.  Animal behavior is also run by instinct, which means that animals cannot generate good karma (which requires intention); they are simply working off their previous bad karma.  The suffering and lack of control make animal birth undesirable.  The conviction that animals are sentient beings underlies the Buddhist ban on  intentionally killing anything, which goes back to the Buddha’s earliest teaching (the Buddha clearly condemned the animal sacrifices prevalent in his time).

This image shows animal life in water, land, and air.  The right side shows wild animals, with domestic animals on the left.  The message here is to respect animal life in all forms.  The resident Buddha has his right hand raised in abhaya mudra (hand upraised with the palm facing out) which means "do not be afraid." 

In a hell (there are many), one is punished for one’s evil actions.  Buddhist visions of hell often link particular punishments with particular sins, doubtless to warn the hearers.  One expiates one’s evil deeds through suffering-hunger and thirst, dismemberment, torture, psychological distress, and so on. Such suffering can last an enormously long time (60,000 years) but is ultimately impermanent, and when one’s term is up, one is reborn in a presumably higher realm.   

This picture shows sinners being cooked, sawed, stabbed, hacked, gnawed, etc., as well as bathing in rivers of pus and other disgusting things.  The resident Buddha has his hand lifted in a teaching gesture 

As in the hells, beings in this realm expiate past misdeeds through suffering. Pretas are described as tormented by hunger and thirst (illustrated by thin necks through which they can never eat or drink enough to satisfy themselves); birth here is described as the result of greed and stinginess in previous lives.  Other torments are psychological, since pretas are believed to remain where they used to live, but to be invisible to the living (which causes aloneness, frustration, isolation, and despair).

Several of this picture's figures have the tiny necks associated with pretas which are the cause of their suffering.  The fighting figures at the lower right, and the person at the bottom enveloped in flame, may reflect the notion that people who suffer violent or sudden death are more likely to become wandering spirits, since they likely had unfinished business or unfulfilled desires. 

The human realm is the only one in which one’s moral choices (good or bad) affect one’s future—in every other realm one is either being rewarded or punished for one’s actions as a human being.  One’s present human condition (e.g., wealth, social status, and physical and psychological qualities) may be based on one’s past karma, but one’s present choices determine one’s future (in this life as well as future lives).  As conscious moral agents, human beings have agency that beings in other realms do not; this clearly underscores the importance of moral action and spiritual development.

The top of half of this picture shows various pursuits: farming, herding, riding a horse, and receiving religious teaching.  The figures on the bottom indicate old age, illness, and death.  The message here is that people must take part in normal life, including earning a living and enjoying oneself  (unless one renounces householder life for religious life, as the monk at top left), but that one must always be conscious of life's final realities.