The Lolita Cover Project, curated by John Bertram, is a fascinating exercise. Dozens of stellar book designers have been approached for their takes on this important 20th century novel. I’m thrilled to be in such good company (see the link for the list of participating designers!)
I thought the image of a cage was fitting, in that Lolita has become trapped in her relationship with Humbert Humbert, but he is equally trapped by his attraction to, as he calls them, nymphets (hence the white cage, to represent their perceived innocence). The bird is ambiguously both inside and outside the cage. The images are from one of my favourite resources for mocking up illustrated covers, vectorstock.com.