No Photo Size Option When Sending Email

On my wife's iPad2 (Model A1403), when emailing a picture from her Photo Library, there is no option to select the picture size being sent. It always sizes down to a minimum. The pictures in her photo library are large -- it's not that they are so small they don't need resizing. This differs from our iPhones, where we can select the picture size before the email is sent. Here, the option does not even come up. Any idea why?