Pull request file attachment at description give error 404

Summary

Bitbucket Server ver4.8.1 showing error 404 and broken image for created pull request that allow attaching an image with special characters in descriptions of a pull request.

Step to Reproduce

1. Create a pull request in a repository.
2. Upon creating pull request, attach an image by the name Screenshot from 2016-07-13 15:16:40.png by clicking on the "paper clip" icon.
   • Preview shows a broken image icon.
3. Proceed with clicking on Create button.
4. Overview tab shows the same broken image icon for the attached image.
5. Click on the image/link, directs to error 404 as attached below.
   

Expected Results

Pop out warning or error message for unsupported file/images names or formats.

Actual Results

Screenshot from 2016-07-13 15:16:40.png

Workaround

1. Rename the image with a proper naming without containing special characters.
2. Then attach the file in the description of pull request.