If you ask an evangelical Christian whether salvation can be had by believing in Jesus Christ, they will almost certainly say yes. Ask the same evangelical Christian whether a soul can seek salvation by believing in, for example, The Universal Life Healing Force, and they will probably emphatically answer no; perhaps followed by a warning of the corruption that is new age belief.
It seems like a simple enough explanation. Jesus is the savior, everyone else is either a superstition, a teacher or philosopher who tried vainly without the light of God, or else a demonic trick. But there is a small, seemingly simple question that makes it a little less obvious. What if, instead of believing Jesus was the way, a group of people believed that Jesu was the way? Most Evangelicals would affirm that this was still a believer, as they would if someone believed in Yesus, Hesus, Esas, or other easily decoded phonetical variations. Especially since even ethnocentric Christians are likely to know that the original Hebrew name of Jesus would have probably been pronounced closer to "Yeshua" than to our English Jesus. So it is not the literal name that is important. It would be interesting to know how much of a switch in name could be tolerated by most evangelicals before they thought what you were talking about is not Jesus. Ezhu? Jozo? Sissy? Edward? Fresno? While the name might not have to be exact, most evangelicals would probably want it to be somewhat related, and obviously not a name with other connotations.
Even if we put aside the often voiced considerations that Jesus did not have the physical appearance that he is often portrayed as having, few thoughtful Christian evangelicals would consider belief or adoration in a graphical image of Jesus to be the same as religious worship of Jesus. Not to say that most Evangelical Christians do not take images of the stereotypical Jesus to be important focuses of devotion, and would be offended by mocking of them, but upon reflection, a physical picture of Jesus, even if it was through some unknown means historical accurate, would not come anywhere near being an adequate vehicle of faith.
The Biblical narrative of Jesus, as told in the gospels, is an important part of knowing what Jesus is. Some Evangelical Christians would claim that knowledge of the outline of Jesus' life, or at least a sincere effort to know them, is a sign of understanding who exactly Jesus is. There is two problems with this: first, although quite a bit is documented about Jesus' life, quite a bit is not. In fact, the gospels, for all their importance, and for all the ornate symbolism developed around specific passages, are fairly lacking in what we would consider normal biographical details. An Evangelical Christian would say that the gospels are historically accurate, but even if we accept that, they are historically sparse. It might seem like a trivial thing to ask, but do we know what Jesus' favorite color was? How much does even the most devoted bible student really know about Jesus, and how much is just an image projected between various stories? But going that far is a little unnecessary, because most Evangelicals wouldn't insist on total knowledge of the life of Jesus as a condition for acceptance. Most would probably consider an illiterate person, who only heard about the story of the crucifixion, and believed in it, to have achieved salvation. If it was an illiterate, and easily confused person, who changed the details around and thought Jesus was drowned, many would consider that person to still understand the essence of the story. Of course, some people might have a stricter standard than this, and it would be interesting to note where and how the line was drawn. Some might think any knowledge was enough, and a few might insist on an entire knowledge of Jesus' life, but some would probably fall in between, and would have varying justifications for their requirements.
The issue of the crucification brings up the idea that the essence of Jesus was his sacrifice, in either its mythical or ethical implications. Perhaps if someone understands the idea of the type of love that would endure torture, humiliation and death to save other people, they could understand Jesus. Some Evangelical Christians might agree that this is adequate to understand Jesus. Many, perhaps most, would not. One of the major points of Christianity is the idea of the uniqueness and actuality of Jesus. Evangelical Christians are often more deeply offended by suggestions that Jesus was just one name for some vague, universal energy than they are by total disbelief. Understanding the idea of sacrifice, without understanding the idea of the actual man who made the sacrifice, whether from the mystical standpoint or an ethical standpoint, does not give someone a total picture.
Ethics is another place where Jesus could be found, but for most probably is not. While most Christians acknowledge that Ethics are an important part of who Jesus is, this is a view also shared by Jews, Buddhists, Muslims, Hindus, and many non-religious people, as well as some agnostics and atheists. Adoption of Jesus as an ethical teacher, even wholeheartedly, is not the same as taking him as a savior.
I have thus examined what exactly it means to believe in Jesus, showing that neither the name, appearance, biography, mystical or ethical understanding of Jesus explains what exactly is believed in, by those who profess Jesus as the way. Notice that by pointing out that I find none of these an adequate explanation, I am not suggesting that professing an belief in Jesus as a savior is untrue, I am just stating that it is not, for me, a simple statement.