Everyone,
So after further review I can see that the code is whitelisting certain image extensions to be displayed inline ('gif', 'png', 'jpg', and 'jpeg'). This is to help prevent code execution attacks (through SVG for example) and other similar attacks. Since Google Docs doesn't add a file extension to the end of the image URL our system sees it as sketchy and removes it. There is no way to change this behavior at this time unless you modify the codebase. You would do so at your own risk as you would potentially open yourself up to different attacks.
Just to note, the setting Allow External Images needs to be enabled for the system to allow any external images in the first place. However, in this case even with the setting enabled those images are stripped as they do not contain an extension to identify itself as to what type of image/file it is.
I will discuss with the team to see if we can improve this in any way but there are no guarantees and no expected timeline. It will simply be added to a list of things to review later on at some point.
Cheers.
