Christ Pantokrator is one of the most common images in Orthodox iconography.

"Pantokrator" is the Greek translation of the Hebrew title El Shaddai, meaning "all powerful." Looser translations are "Ruler of all" or "Sustainer of all." This attribution to Jesus was important given the Christological controversies that tore the early church. The Christ Pantokrator icons were symbols of the Nicene verdict that Christ was co-equal and co-eternal with God. The first icon shown here is the earliest known Christ Pantokrator icon dated around the 6th or 7th Century.

The Christ Pantokrator icons are also called Christ the Teacher. In both icons Jesus is holding a book, sometimes open. Jesus is also making a gesture. Sometimes this is a gesture of blessing and in others it is an oratorical motion. Technically, if the book is closed it is a Christ Pantokrator icon. Christ the Teacher icons have the book open, generally showing a text from either the gospels or Saint John's Revelation.

Beyond the iconic features noted above, I'd just like to point out two other features of curiosity. These are not particularly profound features, just points of interest.

First, in some of the Christ Pantokrator icons you'll notice that the eyes of Christ are asymmetrical. This can be see in the first and second icons shown in this post. You might want to click on them to get a closer look at the eyes.

Why these odd looking eyes? Recall, these icons are representing both the humanity and divinity of Jesus. The speculation is that the two different eyes represent Jesus' dual perspective, finite and infinite. The eyes focus on two different worlds. Seen and Unseen.

A second feature is how in some icons the guesture of Jesus is oddly exaggerated. This can be seen in the third icon of the post. Why the odd hand position?

The hand guesture is exaggerated because Jesus is making the symbol of four letters with the right hand: I, C, and X. These letters spell out Christ's monogram. Specfically, "Jesus Christ" spelled in Greek is:

IHCOYC XPICTOC

The monogram is formed by taking the first and last letters of each name, which is also a symbol of Jesus being Alpha and Omega, the First and the Last:

IHCOYC XPICTOC

Which forms the monogram: IC XC

The monogram is also often written in the halo of Jesus. See this in the second icon. To help you see the letters I zoomed in and traced them out: