@Override
    public long getUniqueId() {
        return ((long)OBJTYPE_TEXTURE << 32) | (0xffffffffL & (long)id);
    }
Determine if the image is NPOT.

@return if the image is a non-power-of-2 image, e.g. having dimensions
that are not powers of 2.
jme3-core/src/main/java/com/jme3/texture/Image.java