The reason why there is no picture of the Prophet (peace and blessings of Allah be upon him)
Question

why is it that there isn't a picture available of the prophet Muhammed[pbuh] anywhere in the world?
Praise be to Allah.Islam came to prevent all means that may lead to shirk or the association of others in worship with Allah. Among these means is the making of images, so sharee’ah forbids making images, and curses the one who does that, and a strong warning is issued to the one who does that. It was narrated from ‘Aa’ishah the Mother of the Believers that Umm Habeebah and Umm Salamah mentioned a church that they had seen in Abyssinia, in which there were images. They mentioned it to the Prophet (peace and blessings of Allah be upon him) and he said: “Those people, if there was a righteous man among them and he died, they would build a place of worship over his grave and put those images in it. They will be among the most evil of creation before Allah on the Day of Resurrection.” (narrated by al-Bukhaari, al-Salaah, 409). 
It was narrated that ‘Aa’ishah (may Allah be pleased with her) said: “The Messenger of Allah (peace and blessings of Allah be upon him) came back from a journey and I had placed a curtain of mine that had pictures on it over (the door of) a room of mine. When the Messenger of Allah (peace and blessings of Allah be upon him) saw it, he tore it and said, ‘The people who will receive the severest punishment on the Day of Resurrection will be those who try to make the like of Allah’s creation.’ So we turned it (the curtain) into one or two cushions.” (Narrated by al-Bukhaari, al-Libaas, 5498). 
It was narrated that ‘Abd-Allah ibn Mas’ood said: “I heard the Prophet (peace and blessings of Allah be upon him) say: ‘The people who will be most severely punished on the Day of Resurrection will be the image-makers.’” (Narrated by al-Bukhaari, al-Libaas, 5494).  
So how could he grant permission to make a picture of him? Hence none of the Sahaabah dared to make a picture or image of him, because they knew the ruling that doing so was haraam.
Allah warns against exaggeration, as He says (interpretation of the meaning): 
“O people of the Scripture (Christians)! Do not exceed the limits in your religion”
[al-Nisaa’ 4:171] 
And the Prophet (peace and blessings of Allah be upon him) warned against doing anything that may involve exceeding the limits concerning him (peace and blessings of Allah be upon him). He said: “Do not exaggerate about me as the Christians exaggerated about the son of Maryam, for I am just a slave, so say ‘The slave of Allah and His Messenger.’” (Narrated by al-Bukhaari, Ahaadeeth al-Anbiya’, 3189). 
Imaam Muhammad ibn ‘Abd al-Wahhaab wrote a chapter entitled “Maa jaa’a ‘an sabab kufr Bani Adam huwa al-ghulw fi’l-saaliheen (What was narrated stating that the reason for the kufr of the sons of Adam was their exaggeration concerning the righteous).”, in which he said: “In al-Saheeh it is narrated that Ibn ‘Abbaas (may Allah be pleased with him) said, concerning the aayah (interpretation of the meaning): 
‘“And they have said: ‘You shall not leave your gods, nor shall you leave Wadd, nor Suwaa‘, nor Yaghooth, nor Ya‘ooq nor Nasr’ (these are the names of their idols).’
[Nooh 71:23] 
– “These were the names of righteous men among the people of Nooh. When they died, the Shaytaan inspired their people to set up stone altars in the places where they used to sit, and call them by their names. They did that but they did not worship them, until those people died, then the knowledge was forgotten and they were worshipped.” 
Ibn al-Qayyim said: “More than one of the salaf said: ‘when they died, the people started to frequent their graves, then they made statues of them, then as time passed they started to worship them.” (Fath al-Majeed Sharh Kitaab al-Tawheed by ‘Abd al-Rahmaan ibn Hasan, p. 219) 
For this reason there are no pictures of the Prophet (peace and blessings of Allah be upon him), because he forbade doing that, lest it lead to shirk. 
The implication of the testimony that Muhammad is the Messenger of Allah (peace and blessings of Allah be upon him) is that we believe in him and in the message that he brought, even though there are no pictures of him. The believers do not need a picture of him in order to follow him. The description of him that is given in the saheeh reports means that we have no need of his picture. Among the descriptions of him (peace and blessings of Allah be upon him) that have been narrated are the following: 
1-He (peace and blessings of Allah be upon him) was the most handsome of face of all people.
2-He had wide shoulders.
3-He was neither tall nor short (of average height).
4-He had a round face with a ruddy complexion.
5-His eyes were intensely black.
6-He had long eyelashes.
7- He was the Seal of the Prophets, the most generous of people in giving, he was the most forbearing and content of all people, he was the most sincere in speech of all people, he had the gentlest nature of all people and was the most easy-going with others. Those who saw him suddenly stood in awe of him and those who mized with him came to love him. Those who described him said they had never seen anyone like him before or since.”
See Sunan al-Tirmidhi, al-Manaaqib, 3571 and other books of Sunnah which give descriptions of the Prophet (peace and blessings of Allah be upon him). 
Undoubtedly the believers wish that they could have met the Prophet (peace and blessings of Allah be upon him). Hence it says in the hadeeth narrated from Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: “From those among my ummah who will love me the most will be those who would come after me, but every one amongst them would have the keenest desire to catch a glimpse of me even at the expense of his family and his wealth.” (Narrated by Muslim, al-Jannah wa Sifat Na’eemihaa, 5060). Undoubtedly love of the Prophet (peace and blessings of Allah be upon him) and following him are the means of being brought together with him in Paradise. Part of loving him (peace and blessings of Allah be upon him) is seeing him in a dream, which means seeing him in his real form. It was reported that Abu Hurayrah said: “I heard the Prophet (peace and blessings of Allah be upon him) say: ‘Whoever sees me in a dream will see me when he is awake, for the Shaytaan cannot take my form.’” Abu ‘Abd-Allah said, Ibn Seereen said: this applies if one sees him in his true form. (Narrated by al-Bukhaari, al-Ta’beer, 6478). 
And Allah is the Source of strength. May Allah bless our Prophet Muhammad.