There's no tool that can convert a complex 2d image in to a 3d model, simply because there is not enough data present in a flat image. Artists can use 3d modeling software and sample images to make models manually.

Simple images, like a 2d logo can easily be made into 3d using simple effects in photo editing software like Photoshop.

If it's an image is a complex one like a person, then it will have to be done manually.