An image of the unannounced Nokia Lumia 925 smartphone has leaked ahead of the device’s official debut, which is expected to take place during Nokia’s press conference on Tuesday. Twitter user @evleaks posted the image on Tuesday morning, and he has a very good track record when publishing photos of unannounced smartphones. Few details surrounding the Lumia 925 can be gleaned from the leaked image — the device obviously features the Windows Phone OS, and it also has a shape that appears to vary slightly from other recent Nokia smartphones. Nokia is expected to unveil the device on Tuesday morning during a press conference in London but in the meantime, the leaked image follows below.