Shared MVC Razor functions in several views

I have functions in my view that is shared by several pages:

@functions 
{
    public HtmlString ModeImage(ModeEnum mode) 
    {
        switch(mode)
        {
            case AMode: new HtmlString("<img etc..."); break;
            // more etc...
        }
    }
}

Is there a way to have it in a separate file and include it on each page without having to copy and paste it in to each one. I know I can write a .cs file and access it per page, but the function really concerns the view and I'de hate to have to recompile if this function changes.