Exodus 32:7–10 (ESV)
7 And the Lord said to Moses, “Go down, for your people, whom you brought up out of the land of Egypt, have corrupted themselves. 8 They have turned aside quickly out of the way that I commanded them. They have made for themselves a golden calf and have worshiped it and sacrificed to it and said, ‘These are your gods, O Israel, who brought you up out of the land of Egypt!’ ” 9 And the Lord said to Moses, “I have seen this people, and behold, it is a stiff-necked people. 10 Now therefore let me alone, that my wrath may burn hot against them and I may consume them, in order that I may make a great nation of you.”
Yes God said they have turned aside quickly out of the way that I commanded them. The arguments goes that God didn’t accuse them of not worshipping Him, but rather accused them turning aside out of the way He commanded them.
But, next verse says “they have made a golden calf and have worshipped it and sacrificed to it…” Now they clearly bowed down and worshipped the Calf! There is no way, one can argue that in Israel’s mind, they were worshipping the Lord in the form of a calf. Its far beyond and bigger than the “form” of worship, it’s the “object” of worship.
Ligon Duncan writes, “ God charges Israel not with departing from him, but from his way, his command of worship. And quoted Sarna notes, “ significantly the text does not say “from me”; they have adopted pagan modes of worship.” 
But I think Israel clearly worshipped the golden calf, as they have taken the golden calf as their God, Yahweh who called Moses to deliver them.
Exodus 32:4 4 And he received the gold from their hand and fashioned it with a graving tool and made a golden calf. And they said, “These are your gods, O Israel, who brought you up out of the land of Egypt!”
After Aaron fashioned the gold into a calf, Israel proclaimed these are their gods! (Clearly Yahweh been reduced to calf now).
Also :Exodus 32:1–2 (ESV)When the people saw that Moses delayed to come down from the mountain, the people gathered themselves together to Aaron and said to him, “Up, make us gods who shall go before us. As for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him.” 2 So Aaron said to them, “Take off the rings of gold that are in the ears of your wives, your sons, and your daughters, and bring them to me.”
Israel asked “make us godswho shall go before us..” Not “make us image of God“. v2 then Aaron started his amazing idol making of the gold from Israelites and formed into a calf.
So my view is that Israel made a major sin by worshipping the golden calf, not worshipping God in the form of a golden calf.
 Philip Ryken editor, Ligon Duncan, Give Praise to God (P&R Publishing, 2011) 39