It is possible, to show original uploaded image files on the image detail view pages though this is not recommended because the HTML layout is designed to accommodate images with a maximum with and height of 630 x 630 pixels.

Should you wish to show an original image file, the HTML code for this is as follows:

<img src="{$image.files.original_url}" width="{$image.files.original_size.0}" height="{$image.files.original_size.1}" />

Full details of all the template variables that can be used on the image detail view pages can be found here.