The image on the left is the Petrine Cross. It is called this because Peter believe he was unworthy to be crucified like Jesus was in the upright position so he requested to be crucified upside down. It has been used incorrectly by certain groups of people as a Satanic symbol when really, to anyone who knows anything about either Christianity or Satanism knows this is no way Satanic or offensive to Christians in anyway.
The image of the right is the Satanic Cross. It is a variation of the alchemical symbol for sulfer which represents fire and brimstone. It can also be interpreted as a combination of the Lorraine cross and the mathematical symbol for infinity, or a phallic re-imagining of the cross, with the infinity symbol representing a scrotum. It is often interpreted as a symbol of Satanism, because LaVey adopted it from the Cross of Lorraine or even the Patriarchal cross, which is also a symbol of Christianity and Hermeticism. Hermetic alchemists of the Renaissance used the emblem as a symbol of earth and spirit by combining the square earth cross with the cross of Christ. When drawn symmetrically, it symbolised the hermetic maxim.
The image of the left = you thinking you’re unworthy of Jesus.
The Image on the right = the actual Satanist cross.