The following is an excerpt from a dialogue with my language partner. For some context, I told her that I went to the restaurant with my girlfriend and her family on christmas eve. She then replied the following:
My attempt at translation:
"I enjoyed reading your story about the christmas-eve-meal. In Japan, there is the impression that..."
So, I think that 恋人同士で行く is an attribute to イメージ which itself is part of the sentences predicative via the copula です(ね). I think 恋人同士で行く means "To go as a couple (literal: To go being a couple). My main issue is that I have little to no idea how to connect that with クリスマスイブディナーというと.
From my more recent questions, I've learned that という can put the two elements on both sides into a "A = B" relationship. Then, whenever と isn't used as a quotative or conditional particle, and when it also doesn't connect two nouns like "ミラーさんと田中さんはもう帰りました。", my last idea would be the functionality of "AとBは違います。" = "A differs from B".
However, if the latter should be the case, then it really gives me a headache how to integrate クリスマスイブディナーという and 恋人同士で行くイメージですね into each other, especially since I also dont really know how to handle the direct succession of と to という.