An image of one page of a PDF, a PNG of a submission's page or a JPEG of a template's.
@type t() :: %Docspring.Model.PageImage{ content_type: String.t(), download_url: String.t() | nil, filename: String.t(), height: integer(), page: integer(), permanent_url: String.t() | nil, sha256: String.t() | nil, size: integer(), width: integer() }