1)
Who will go back?
1.
Radak: The idolaters will be shamed, and all who trust in them will retract from their thinking.
2.
Malbim: There are two kinds of idolaters. (a) They know that there is a first Cause and Elokim, just they considered the idol a intermediary between them and Hashem. They are "those who trust in an image." They trusted to receive their request via it. They will see that it does not help, and not trust in it any more. (b) Refer to 42:17:2:1.
2)
Who will be ashamed?
1.
Malbim: Some idolaters totally denied Hashem's existence, and attributed divinity to the image. They say to it "you are our gods." They will retract, and also be ashamed of their great folly.
