Also read the authentic narrations at the following link on the authority and power of the Imam's (as) over life and death and the status of the AhlulBait (as):

Imam's (as) control over life and death

Status of the AhlulBait (as)

Mufawwezah or Muqasserah?? 

Imam Reza (as) on the issue of Ghulw:

Quoting only a part of a very lengthy narration:

إذ يعلموا أنه القادر بنفسه الغني بذاته، الذي ليست قدرته مستعارة ولا غناه مستفادا، والذي من شاء أفقره ومن شاء أغناه، ومن شاء أعجزه بعد القدرة، وأفقره بعد الغنى، فنظروا إلى عبد قد اختصه الله بقدرة ليبين بها فضله عنده، وآثر بكرامته ليوجب بها حجته على خلقه، وليجعل ما أتاه من ذلك ثوابا على طاعته، وباعثا على اتباع أمره، ومؤمنا عباده المكلفين من غلظ من نصبه عليهم حجة ولهم قدوة

"It is so because they do not realize that God is All-powerful on his own and Needless by his self. He is the One whose might/power is not borrowed from any one and his needlessness is not due to help from any one."

"He is the one who makes poor whomsoever He wills and makes rich whomsoever He wills and make whomsoever He will incapable after having ability and make whomsoever imporvished after being rich."

"They saw a God’s selected servant, to whom He gave a particular power so that they may realize his gracefulness in God’s sight. God gave him some kind of miracle, so that people could realize that he is proof of God’s might; so that God may make that gentleman’s greatness a reward of His obedience and also make him a means of His obedience; so that God may, by appointing such a graceful gentleman their leader, protect His responsible servants from any doubt as to who is God’s Hujjat and who is their role model."

Then Imam Reza (as) gives an example and then says the following:

كذلك هؤلاء لما وجدوا أمير المؤمنين عبدا أكرمه الله ليبين فضله، ويقيم حجته، فصغروا عندهم خالقهم أن يكون جعل عليا له عبدا، وأكبروا عليا عن أن يكون الله عز وجل له ربا، فسموه بغير اسمه فنهاهم هو وأتباعه من أهل ملته وشيعته وقالوا لهم: يا هؤلاء أن عليا وولده عباد مكرمون مخلوقون ومدبرون لا يقدرون إلا على ما أقدرهم عليه لله رب العالمين، ولا يملكون إلا ما ملكهم، ولا يملكون موتا ولا حياة ولا نشورا، ولا قبضا ولا بسطا، ولا حركة ولا سكونا إلا ما أقدرهم عليه وطوقهم، وأن ربهم وخالقهم يجل عن صفات المحدثين، ويتعالى عن نعت المحدودين، وأن من اتخذهم أو واحدا منهم أربابا من دون الله فهو من الكافرين وقد ضل سواء السبيل

"Likewise, this community has found Amir Al Momineen (as) a chosen servant of Allah. Almighty Allah has, through His special mercy, made him honorable so that he may show the creation the greatness of Almighty Allah and may establish His Proof before them. So, in the view of these people, their Creator is unable to create Ali (as) and that Ali (as) cannot be His slave and raised Ali (as) above that Allah is his Lord. With this view, they gave God’s Name to this slave of God."

"When Amirul Momineen Ali (as) and his true follower Shias saw this faulty attitude of this group, they prevented them from doing so. They told them that Ali (as) and his pious progeny are the honored servants of the Almighty Allah. God has given them grace but they by themselves are not able to do anything, except what God has given them power to do. They do not have anything, except which God has granted them. They have no say in the matter of life, death and rising after death, need, needlessness, movement, stagnancy, except on what God has granted them power to do. His Lord and Sustainer and Creator is higher than all the virtues of virtuous people and He is Higher than what anyone can ever imagine. Anyone who considers all of them or any one of them as lord apart from Allah, then he is from the disbelievers and he has deviated from the right path."

[Source: Al-Ehtejaaj, Vol. 2, Pg. 232-233]

Tafweed and Incident of Husain bin Rooh:

منها ما أخبرني به الحسين بن عبيد الله، عن أبي عبد الله الحسين بن علي بن سفيان البزوفري رحمه الله، قال: حدثني الشيخ أبو القاسم الحسين بن روح رضي الله عنه قال: اختلف أصحابنا في التفويض وغيره، فمضيت إلى أبي طاهر بن بلال  في أيام استقامته فعرفته الخلاف، فقال: أخرني فأخرته أياما فعدت إليه فأخرج إلي حديثا باسناده إلى  أبي عبد الله عليه السلام قال

إذا أراد [الله] أمرا عرضه على رسول الله صلى الله عليه وآله وسلم، ثم أمير المؤمنين عليه السلام [وسائر الأئمة]  واحدا بعد واحد إلى (أن)  ينتهي إلىصاحب الزمان عليه السلام ثم يخرج إلى الدنيا، وإذا أراد الملائكة أن يرفعوا إلى الله عز وجل عملا عرض على صاحب الزمان عليه السلام، ثم (يخرج)  على واحد [بعد]  واحد إلى أن يعرض على رسول الله صلى الله عليه وآله وسلم، ثم يعرض على الله عز وجل فما نزل  من الله فعلى أيديهم، وما عرج إلى الله فعلى أيديهم، وما استغنوا عن الله عز وجل طرفة عين

Narrated by Sheikh Abu ul Qasim Hussin bin Rooh, who said that

"There was a difference of opinion about Tafweed and about other things in our companions. So I went to Abu Tahir bin Bilal in his days of steadfastness and informed him about this. He said: Wait for some days. I went to him again and he narrated a narration with his chain to Imam Abu Abdullah Imam Sadiq (ع) who said:

When Allah decides for something, he presents that to Prophet (ص) asws, then Imam Ali (ع), and then All Aimmah (ع) one after another till it reaches the Imam of the Time (ع), and then it is given to this world. And when Angels decide to raise something to Allah, they present it to the Imam of the Time (ع), then it passes from one to other (Imam) till it reaches Prophet (ص), then it is presented to Allah (عز و جل). So What is revealed from Allah, is through their hands, and what is raised to Allah, is through their hands. And they (the Imams) are not free of Allah (عز و جل) even for a blink of an eye."

[Source: Al-Ghayba - Sheikh Toosi, Pg. 387]

Taken from: http://ahlubait.wordpress.com/2013/02/16/tafweed/

Another similar narration:

حدثنا محمد بن عيسى عن يونس بن عبدالرحمن عن بعض اصحابه عن ابى عبد الله عليه السلام قال سمعته يقول ليس شئ يخرج من الله حتى يبدأ برسول الله صلى الله عليه وآله ثم بامير المؤمنين ثم واحدا بعد واحد لكى لايكون اخرنا اعلم من اولنا

Narrated that Abu Abd-Allah Imam Sadiq (عليه السلام) said,

"Nothing comes from Allah (عز وجل) unless its beginning from the Prophet (صلى الله عليه وآله) then Amir al-Mumineen (عليه السلام) and then one by one and our last one is not more knowledgeable than our first."

[Source: Basaair al-Darajat, Pg. 116]

Quranic Verse 1:

وَمَا تَشَاءُونَ إِلَّا أَن يَشَاءَ اللَّهُ إِنَّ اللَّهَ كَانَ عَلِيمًا حَكِيمًا

“But You will not, except as Allah wills; for Allah is full of Knowledge and Wisdom” [Quran 76:30]

This verse clearly answers the objection of Tafweez. It simply and clearly proves that whatever the AhlulBait (as) do is always as per and under the will of Allah (swt) and not independent of Allah (swt) and hence such a belief is not Tafweez.

This very clear narration on Tafweez makes things crystal clear:

ثم قال : وجئت تسأله عن مقالة المفوضة ، كذبوا، بل قلوبنا أوعية لمشية الله ، فإذا شاء شئنا ، والله يقول :وما تشآؤون إلاأن يشآء الله

ٍImam Mahdi (عليه السلام) said,

"You have come to ask about the Mufaw'wizah. They (Mufaw'wizah) have lied. But our hearts are containers of the Will of Allah (عز وجل), so when Allah wills, We will. And Allah (عز وجل) has said, "And you will not will, but as Allah Wills" (76:30)

(only small part quoted here)

[Source: Al-Gaibha - Sheikh Toosi, Pg. 159]

The following set of Ahadith further support this:

حدثنا محمد بن جعفر قال حدثنا محمد بن أحمد عن أحمد بن محمد السياري عن فلان عن أبي الحسن عليه السلام قال: إن الله جعل قلوب الأئمة موردا لإرادته فإذا شاء الله شيئا شاؤه وهو قوله وما تشاؤن إلا يشاء الله رب العالمين

Narrated that Abu al-Hasan Imam Kazim (عليه السلام) said,

“Verily Allah (عز وجل) has made the hearts of the Imams the source/place of this Will. If Allah (عز وجل) wills something, They also Will the same. And is the saying, "And you will not will, but as Allah Wills." (76:30)

[Source: Tafseer Al-Qummi Vol.2 Pg. 409]

Another narration on the same lines:

ومنه يرفعه إلى ابن أبي عمير عن المفضل عن أبي عبدالله عليه السلام قال : لو اذن لنا أن نعلم الناس حالنا عند الله ومنزلتنا منه لما احتملتم ، فقال له : في العلم ؟ فقال : العلم أيسر من ذلك ، إن الامام وكر  لارادة الله عزوجل لا يشاء إلا من يشاء الله

Narrated that Abu Abd-Allah Imam Sadiq (عليه السلام) said,

"If we were permitted to make the people know Our situation near Allah (swt) and our status from Him, you will not (be able to) bear/carry it."

The narrator said, "In (about) knowledge?"

Imam (عليه السلام) said, "Knowledge is the easiest of that. Indeed, the Imam is the place (nest) of the Will of Allah (عز وجل), They do not will but what Allah (عز وجل) Wills."

[Source: Bihar Al-Anwar, Vol. 25 Pg. 385]

And the below narration clarifies things further:

الحسين بن محمد الاشعري، عن معلى بن محمد، عن أبي الفضل عبدالله بن إدريس، عن محمد بن سنان قال: كنت عند أبي جعفر الثاني عليه السلام فأجريت اختلاف الشيعة، فقال: يا محمد إن الله تبارك وتعالى لم يزل متفردا بوحدانيته ثم خلق محمدا وعليا وفاطمة، فمكثوا ألف دهر، ثم خلق جميع الاشياء، فأشهدهم خلقها وأجرى طاعتهم عليها وفوض أمورها إليهم، فهم يحلون ما يشاؤون ويحرمون ما يشاؤون ولن يشاؤوا إلا أن يشاء الله تبارك وتعالى، ثم قال: يا محمد هذه الديانة التي من تتدينها مرق ومن تخلف عنها محق، ومن لزمها لحق، خذها إليك يا محمد

Al-Husayn ibn Muhammad al-Ash’ari has narrated from Mu‘alla ibn Muhammad from abu al-Fadl ‘Abd Allah ibn Idris from Muhammad ibn Sinan who has said the following.

"Once I was in the presence of Abu Jafar (as), the second, and I mentioned the differences among the Shi‘a."

The Imam (as) said, "O Muhammad, Allah, the Most Holy, the Most High, is One eternally. He created Muhammad (saww), Ali (as) and Fatima (sa). They were there for a thousand Dahr (time less time in philosophy, a turn). Then He created all other things. He made them to witness the creation of all other things, made obedience to them obligatory and gave control (Fawaz) of the affairs of the creation. They can, thus, make lawful whatever they would wish and unlawful whatever they would wish and they would never wish anything unless Allah, the Most Holy, the Most High, would wish."

He then said, "O Muhammad, this is a religion that if overdone, it would lead to extremism and if ignored, it would be degradation and those who would hold to it properly would have proper contact. Keep it with you, O Muhammad."

[Source: Al-Kafi, Vol. 1 Pg. 441]

The above narrations makes it absolutely clear that the belief of Tafweez that is condemned by the Imam's (as) is only when it is believed that the actions of the AhlulBait (as) are independent of the Will of Allah (swt).

So if the Imam’s (as) were to give life to the dead, or to create a lion out of a picture, then as per the above verse of the Holy Quran and the above narrations, this will always be as per the will of the Allah (swt) and hence cannot be called Tafweez (delegation of authority from Allah (swt) to the Imam's (as)).

Read here for Imam's control over life and death.

Quranic Verse 2:

اطِيعُوا اللَّهَ وَ أَطِيعُوا الرَّسُولَ وَ أُولِي الْأَمْرِ مِنْكُمْ

"Obey Allah, and obey the Messenger, and those charged with authority among you" [Quran 4:59]

The question that this verses poses is “Authority over what matter?” What is the ‘Amr’ in this verse? The below Hadees answers this question. 

و فيه و قد ذكر عليه السلام الحجج قال السائل: من هؤلاء الحجج؟ قال: هم الرسول الله و من حل محله من أصفياء الله و هم ولاة الأمر الذين قال الله فيهم: «أَطِيعُوا اللَّهَ وَ أَطِيعُوا الرَّسُولَ وَ أُولِي الْأَمْرِ مِنْكُمْ» و قال فيهم: «وَ لَوْ رَدُّوهُ إِلَى الرَّسُولِ وَ إِلى‏ أُولِي الْأَمْرِ مِنْهُمْ لَعَلِمَهُ الَّذِينَ يَسْتَنْبِطُونَهُ مِنْهُمْ» قال السائل، ما ذاك الأمر؟ قال على عليه السلام، الذي به تنزل الملئكة في الليلة التي يفرق فيها كل امر حكيم من خلق أو رزق و أجل و عمل و حيوة و موت، و علم غيب السموات و الأرض، و المعجزات التي لا ينبغي الا الله له و أصفيائه و السفرة بينه و بين خلقه

The person said, "Who are these Hujjaj?"

Imam Ali (as) said, "They are Prophet of Allah (saww) and those who succeeded him who are selected by Allah (swt) and they are the Wali-Amr (gaurdians) regarding them Allah (swt) says,

"Obey Allah, and obey the Messenger, and those charged with authority among you" [Quran 4:59]

And says,

"If they had only referred it to the Messenger, or to those charged with authority among them, the proper investigators would have Tested it from them" [Quran 4:83]

The person said, "What is that Amr?"

Imam Ali (as) said, "That (Amr) is with which the angels descend in the night in which all the wise matters (Amr) are distinguished, from creation (Khalq), livelihood (Rizq) and life and death and the unseen knowledge of the heavens and the earth and the Miracles that is not for any one but Allah and his selected ones and he means between Him and this creations." 

[Source: Al-Ehtejaaj Vol. 1 Pg. 252]

Quranic Verse 3:

فَتَبَارَكَ اللَّهُ أَحْسَنُ الْخَالِقِينَ

"So blessed be Allah, the best of the creators" [Quran 23:14]

The above verse of the Holy Quran clearly speak out that  Allah (swt) is not just the Creator... Allah (swt) is the “Best Creator".

The below narration clarified things further:

قلت: جعلت فداك وغير الخالق الجليل خالق؟ قال: إن الله تبارك وتعالى يقول: (تبارك الله أحسن الخالقين) فقد أخبر أن في عباده خالقين منهم عيسى ابن مريم، خلق من الطين كهيئة الطير بإذن الله فنفخ فيه فصار طائرا بإذن الله، والسامري خلق لهم عجلا جسدا له خوار

Fath bin Yazeed says to Imam Raza (as), "May I be sacrified on You. Is there any creator other than Great Creator (Allah)"?

Imam Raza (as) said, "The Almighty Allah (swt) says: ' So blessed be Allah, the best of the creators'. He (Allah) has informed that amoung his creations are creators, from among them is Isa bin Maryam (as), who created from clay the body of a bird by the will of Allah (swt) then breathed into it and it became a bird by the will of Allah (swt) and (from among them is) Samiri who created for them a calf, its body mooing" ...

(Part of a long Hadees, only the relevant porting quoted here)

[Source: Al-Tauheed, Sheikh Sadooq Pg.63]