Aegon the Conquerer. The prototypical Targaryen. A warrior, tall, powerful, broad shouldered. Very charismatic and commanding. Should be shown in his battle armor, perhaps a shirt of black scales, greaves, gauntlets, a flowing cloak. His sword in hand (Blackfyre, a Valyrian steel blade). His hair cut short, no longer than the bottom of his ears. His crown is a simple circle of Valyrian steel set with big square-cut rubies.

A weakling. As tall as his father Aegon, but softer looking. Slender, weedy, dreamy. Paler eyes than Aegon, more lilac than purple. His hair curled and perfumed, all in ringlets, falling to his shoulders. A silky beard and mustache, sort of a "Three Musketeers" look, coming to a point. Dressed in velvet robes, the same lilac as his eyes, with cloth-of-gold lining and an ermine collar. Gold rings and gemstones on long, slim fingers. A different crown; this one is all gold, much larger and more elaborate. No armor. Instead of a sword, he holds a wine cup in the portrait: gold, encrusted with gems. His smile should be somehow tenuous, nervous, anxious to please.

Maegor the Cruel. Another warrior. A big man, even taller than his father Aegon, bull-like, heavy shoulders, thick neck, huge arms. On the heavy side, but more massive and square than fat. Nothing soft about him. Short hair, short beard that follows the jawline. Angry, suspicious eyes, scowling mouth. Just looking at him, you know this man is hard and brutal. No wine cup here; it's the sword again. His armor is more elaborate than Aegon's. Instead of a shirt of scale, he wears a breastplate, covered by a surcoat that displays the Targaryen three-headed dragon, red on black. He looks as though he has just come from battle, and his armor and cloak show dints, tears, bloodstains. He wears Aegon's steel-and-ruby crown, not Aenys's elaborate one.

The Old King. The Conciliator. Jaehaerys reigned for fifty-five years. Let's show him late in his reign as an old man, as that is how he is best remembered. Wise and dignified. Despite his years, still unstooped, but his face and hands are wrinkled, and his long white beard reaches to his waist. Dressed in flowing robes of black and gold. His crown is a simple gold band set with seven gemstones of different colors. In his hands, instead of sword or wine cup, he holds a quill pen for writing.

A plump and pleasant king, raised during a time of peace and plenty. Round-faced, smiling, jolly. In his forties. No beard, but a bushy silver-gold mustache. Wearing the Jaehaerys crown, with the seven stones. Looks as though he would be great fun at a party, always telling jokes. Clad in silk brocade, dark purple.

The Dragonbane. Clad all in black, even to his gloves. A three-headed dragon on a golden chain around his neck. Pale, lean, unsmiling. A very somber look. He looks sad, marked by the grief he carries with him. It is hard to picture him smiling. A short beard, but no mustache. His crown is a slender gold band, no ornament.

The Young Dragon. Only fourteen when he ascended to the throne. A warrior and conquerer. Young, clean-shaved, very handsome, long hair. Clad in an elaborate suit of gold-and-black plate, with his sword in his hand. Smiling, self-confident, very charismatic. The Alexander the Great of Westeros. He should probably be shown outdoors, with the red mountains of Dorne in the background, and his army, horses, tents, etc. Wears the Aegon crown, the steel and rubies.

Baelor the Blessed. Baelor the Beloved. The septon king. No sword or armor here, only a septon's white robes tied off with a rope belt. A young man, in his early twenties, but very thin (from repeated fasts) and frail looking, with a gentle, almost beatific smile (think Jesus). One hand raised in blessing, the other holding a holy book (black leather, with a seven-pointed star stamped on the cover in gold leaf). His long hair and beard remind one of Jesus too, although Baelor's are the typical Targaryen silver-gold color. Wears a crown of flowers and vines.

Came to the throne quite late, when he was in his fifties. Clean-shaved, with long hair, a prominent nose, bushy eyebrows, a shrewd and calculating look about his mouth and eyes. Coins in his hand. He wears the simple crown of Aegon III Dragonbane.

Amiable, clever, sickly (he died young). Pale and frail, with very large purple eyes. Shoulder-length hair, a silky beard, a tired smile. One arm concealed by the drape of his cape. Wears Maekar's crown.

Bookish. Spindly and stooped, his robes rich and elaborate but soiled, as if he has forgotten to change them. Long straight hair, long thin face, long thin mustache, long pointed beard. In his hand is an old scroll, and other books and scrolls are visible in the portrait. His eyes red-rimmed from reading.

There's an excellent depiction of a younger Maekar in THE HEDGE KNIGHT graphic novel. As king, Maekar would look much the same, only older. A certain weariness about him, but strength as well. Armored, with a spiked mace in his hand (blood on one of the spikes). His crown is black iron and red gold, sharply pointed. His surcoat shows his personal arms; the Targaryen three-headed dragon, four times (two above, two below).