What is similar about these two images?

Both depict a person(s) who is prepared to die for what they believe.

Both are acts of submission. The motivation is identical – through death, to testify to a truth which they are prepared to pay the ultimate price.

Both believe in a reward for their sacrificial death.
 
Islam is an ideology that promotes martyrdom by promising paradise to those who lose their lives for the cause of Allah. Islam means submission. A good Muslim is prepared to die (martyrdom) in the course of this submission. In the words of Muhammad: “I would love to be martyred in Allah’s Cause and then get resurrected and then get martyred, and then get resurrected again and then get martyred and then get resurrected again and then get martyred.” This is why modern-day Jihadists often say that they love death. “Suicide bomber” is a derogatory term invented in the West to describe what in Islam is known as a Fedayeen – a martyr. The point of the bomber isn’t suicide – it is to kill infidels in battle.  This is not just permitted by Muhammad, but encouraged with liberal promises of earthy rewards in heaven including food and sex (72 virgin maidens).
 

            And think not of those who are killed in Allah’s way as dead. Nay, they are alive

being provided sustenance from their Lord. Quran 3:169

 
Adherents to the Christian faith also see death as a victory and heaven (paradise) as a place of ultimate peace, joy and rewards. Followers of Christ are encouraged to glorify God in life and death. “They [the faithful] did not love their life even when faced with death.” (Rv.12:1). Dietrich Bonhoeffer, renowned Lutheran pastor, theologian and martyr for his faith by the Third Reich (1945) stated succinctly and profoundly, “When Christ calls a man, He bids him come and die.” In their conviction and willingness to die for their faith, Islam and Christianity are identical.
 
What is different about these two images?

One celebrates death, the other life:

         The purest joy in Islam is to kill and be killed for Allah.” I. Khomeini

          Whoever loses his life for My sake will find it. Jesus Christ

One is based in truth, the other in lies. One conviction based on religious propositions, the other based on first-hand personal experience.
 
Death by martyrdom proceeds from an identification (with a person or a cause) that is so total and complete it takes over a life even unto death. Death is preferable if it serves as a statement (testimony; witness); a way of moving forward a cause. Consider these quotes from famous American patriots:

“Give me liberty or give me death” Patrick Henry
“I only regret that I have but one life to give for my country” Nathan Hale

An important part of our Christian heritage are those who have given their lives as martyrs beginning with Stephen; (James; the Apostles, Polycarp; Justin Martyr, Joan of Arc, William Tyndale, John Huss, Jim Elliot & Nate Saint). In any recent year, there have been more Christian martyrs than in ancient times.
 
The word martyr comes from a Greek word, martur or marturia which means to be a witness, to testify, to give evidence or testimony, to bear record, to affirm (give proof) that one has seen or heard or experienced something. The analogous context is a courtroom setting. In our modern vernacular, a martyr is a person who is killed (or will die) for religious or other beliefs. The powerful truth is a Christian witness (martyr) has become a martyr long before they give their life. The call to “take up our cross daily” is a call to martyrdom, maybe in physical death for some… but for sure it’s a call to be living martyrs. We who follow Jesus have a call to die to ourselves, each day.

“I’m convinced that by the time a Christian martyr is confronted with death, s/he

has already died a thousand deaths, by living for God.” Anon

 
Being a witness is an identity – a lifestyle. It is an essential part of who we are as a follower of Jesus. Witness is not just something we do. To be filled with the Spirit is to be clothed with power from heaven. This power enables me to submit my life to be a witness to the uttermost. I will stand for truth, which I have personally experienced, and for which I will give my last breathe and ounce of blood. Being a witness each day is living a martyr’s life.