I guessed with a cover like that, it must have been a soundtrack to something and I did find two soundtracks for movies called "Jeans." However, the first is an Indian film and the cover doesnt fit. The second one has a cover that comes very close to what you described, only you see a lot more of the girl.

Jeans Soundtrack

Not exactly classical though. If you want a laugh, listen to the soundclip for the first song. Mannnnnn, they did a lot of acid back in the 70s!!!
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With great power comes Awesome irresponsibility.