Praise be to Allah.
The focus of the prohibition on drawing and making images is the face, because that is the original purpose of drawing, to the extent that if the word “image (soorah)” is used in general terms, it is understood as referring to the face.
It was narrated from Suwayd ibn Muqarrin (may Allah be pleased with him) that someone slapped a slave woman of his, and Suwayd said to him: Do you not know that hitting the face [soorah] is haraam?
Al-Haafiz ibn Hajar said in Fath al-Baari (1/176): That is, the face which it is not permissible to hit. End quote.
If the features of the face do not appear in the picture, it no longer has that which would make it disallowed and forbidden.
This is indicated by the report narrated from Abu Hurayrah (may Allah be pleased with him), according to which the Messenger of Allah (blessings and peace of Allah be upon him) spoke of what Jibreel (peace be upon him) said to him: “So tell someone to cut off the head of the statue that is in the house, so that it will become like a tree.” Narrated by Abu Daawood (4158) and by at-Tirmidhi (2806), who said: It is hasan saheeh. It was classed as saheeh by al-Albaani in Saheeh Abi Daawood.
Ibn Qudaamah said in al-Mughni (8/111).
If the head of the image is cut off, it is no longer makrooh (disliked). Ibn ‘Abbaas said: The image [soorah] is the head, so if the head is cut off, then it is no longer an image. This was narrated from ‘Ikrimah. End quote.
Shaykh Ibn ‘Uthaymeen said – as noted in Majmoo‘ al-Fataawa (2/278, 279):
If the image is not clear – that is, it has no eye, nose, mouth or fingers – then it is not a complete image, and it is not competing with or trying to match the creation of Allah, may He be glorified and exalted. End quote.
The Shaykh also said in Liqaa’aat al-Baab al-Maftooh (no. 150, question no. 23), when he was asked about the ruling on depiction of a human being from behind, and he was surprised by that and wondered what the purpose of it was, then he said:
If that happens, then it is not an “image”, meaning that it is like a shadow, just as a person walking in the sun has a shadow. End quote.
Based on that, there is nothing wrong with drawing and depicting a person from behind.
See also the answer to question no. 102988.
And Allah knows best.