def getBoundingBoxForImage(img, hdr):
    """Get the bounding box for the an image from a TPF file
    i.e the corners of the rectangle that circumscribes the image

    Inputs:
    ---------
    img
        (2d np array) Image to construct bounding box for
    hdr
        (FITS header object). The header of the first extension of the TPF
        file. If you are dealing with an image not from a fits file, use
        img.shape to get the bounding box instead.

    Returns:
    ----------
    A 4 element list for column0, column1, row0, row1

    """
    shape= img.shape
    c0 = float(hdr['1CRV4P'])
    r0 = float(hdr['2CRV4P'])


    extent = [c0, c0+shape[1], r0, r0+shape[0]]
    return extent