Can switching images and documents to an Azure blob hostname affect SEO?

Question

Hear me out, I know it's a strange question.

Consider a scenario in which all the images and PDFs are hosted on the same domain as the pages:

https://www.themainhostname.com
https://www.themainhostname.com/page-something
https://www.themainhostname.com/images/a-random-image.jpg
https://www.themainhostname.com/docs/some-random-document.pdf

For availability reasons and as sort of a homegrown CDN, we set up an Azure blob as the storage provider in the content management system. The default endpoint for Azure Blob storage is .blob.core.windows.net.

Thus, the images and PDFs will served from that hostname going forward:

https://www.themainhostname.com
https://www.themainhostname.com/page-something
http://<storage-account-name>.blob.core.windows.net/images/a-random-image.jpg
http://<storage-account-name>.blob.core.windows.net/docs/some-random-document.pdf

Now let's say that a whole bunch of these images and PDFs appeared in search results for specific keyword searches.

After switching to Azure blobs for the media files, whatever keyword searches returned said media in SERPS now resolve to this Azure hostname, .blob.core.windows.net.

BrightEdge and Alexa call this "share of voice," and I understand it to represent what % of a SERPs for a given keyword search are represented by a given hostname. I know empirically that switching to Azure storage reduces share of voice - but does this translate to affecting rankings in any way?

Answer 1

Due to my experiences in using CDNs it is not important where the images are located. The context matters and you do not change the context!

I guess you will not losing your rankings because using a CDN is a benefit for the user when you look at global availability, performance and security. Furthermore, your local server will get faster to do its core tasks (that means not wasting performance to serve static docs or images). And this will be also a good point why you will not lose your rankings (page speed, in general, will become better).

Tiny Advice for the future: I hope I will not break your internal architectural rules but ... It would be better to use a subdomain and using a CNAME like https://static.themainhostname.com. Your origin will be http://<storage-account-name>.blob.core.windows.net. It has to do with load balancing and maintainability! (but I don't know if that is possible in azure)