procedure TCard.ColValueGetProperties(Sender: TcxCustomGridTableItem;
  ARecord: TcxCustomGridRecord; var AProperties: TcxCustomEditProperties);
begin
  if Assigned(ARecord) = False then Exit;

  case Integer(ARecord.Values[ColParameterTypeKey.Index]) of
    prtText: AProperties     := erTypeText.Properties;
    prtInteger: AProperties := erTypeInteger.Properties;
    prtFloat,
    prtFormula: AProperties := erTypeFloat.Properties;
    prtDate   : AProperties := erTypeDate.Properties;
    prtBoolean: AProperties := erTypeBoolean.Properties;
    prtImage  : AProperties := erTypeImage.Properties;
  end;
end;

// Параметры.
function TOutpatientCard.GetParametersJSON: string;
  var Count  : Integer;
      JSONArr: TJSONArray;
      JSONObj: TJSONObject;
      S      : string;
      B      : Boolean;
      Base64 : TBase64Encoding;
begin
  JSONArr := TJSONArray.Create;
  try
    with Parameters.DataController do
      for Count := 0 to RecordCount - 1 do
      begin
        JSONObj := TJSONObject.Create;

        if (VarIsNull(Values[Count, ColValue.Index]) = False) then
          case Integer(Values[Count, ColParameterTypeKey.Index]) of
            prtText     : JSONObj.AddPair(TJSONPair.Create(fnMDL_PrText,            string(Values[Count, ColValue.Index])));
            prtInteger: JSONObj.AddPair(TJSONPair.Create(fnMDL_PrInteger, TJSONNumber.Create(Integer(Values[Count, ColValue.Index]))));
            prtFloat,
            prtFormula: JSONObj.AddPair(TJSONPair.Create(fnMDL_PrFloat,   TJSONNumber.Create(Currency(Values[Count, ColValue.Index]))));
            ...
            ...
            // ТУТ ВОПРОС:
            prtImage  :
            begin
              Base64 := TBase64Encoding.Create(-1, '');
              try                                              
                JSONObj.AddPair(TJSONPair.Create(fnMDL_PrImage, Base64.EncodeBytesToString(Values[Count, ColValue.Index])));
              finally
                Base64.Free;
              end;
            end;
          end;

        // Сохраняем объект в массив.
       JSONArr.AddElement(JSONObj);
      end;

      Result := JSONArr.ToString;
  finally
    JSONArr.Free;
  end;