Rendering a description with images using the wiki mapping is changing the image dimensions

When using the mapping ${wiki:Description} to export an issue which contains an image, in the final document, the image will be resized and doesn’t maintain the original proportions.

For example, given an image with size 1647 × 882 px, in the final document the image size was increased by 57% to 2585x1384 px, which is causing some images to go over the document margins, as verified in the following file: Template_Bug_Graphics-1.docx

Depending on the size of the original image uploaded to Jira, this behavior changes in some cases, where instead of increasing the dimensions of the image it might reduce them instead, even though the correct sizes are returned by Jira in rendered fields and for the attachments.

How to reproduce

1. Create an issue and add an image to its description, using for example the attached image: 27x14.png; 
2. Attempt to export the issue using a template containing the ${wiki:Description} mapping.

Actual Result
The image dimensions are changed in the final document depending on the original size of the image.

Expected Result
The image should retain the same image size, returned by Jira, for the uploaded file.