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:
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:
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?