Downloading users' avatars from People Directory occasionally saves without file extension

Summary

If you want to download a copy of a user's avatar from People Directory to use elsewhere, you can right-click the avatar, and select Save Image As... and it will prompt to download with a file name hash in the form of a .png file.

For certain avatars, the .png file extension isn't automatically added, and the image is only saved as user-avatar.

On a Mac, this then is assumed to be a TextEdit file.

Environment

• Confluence Cloud 1000.0.0-02447c1
• Replicated on Mac OS 10.11.6
• Chrome versions 61.0.3163 and 62.0.3202
• Safari version 11.0.1

Steps to Reproduce

1. Navigate to People Directory
2. Right-click on a user avatar and Save Image As...
3. Continue this for multiple users until one does not download with the .png file type

Expected Results

All images should download with .png extension.

Actual Results

Occasionally images will not download with .png file type.

Working image:

Non-working image:

Notes

Untested yet on Windows

Workaround

The image still appears to download correctly, as I am able to open it automatically in Preview.
You can append .png to the end of the file. The computer will ask you to confirm this, but once you do, the thumbnail loads properly as well and the info screen confirms it is indeed a .png file type.