For Microsoft Forms file uploads, the files are stored in the Form owner's OneDrive for Business for personal forms, under the Microsoft Forms folder. Microsoft explicitly documents this storage behavior.
I would approach your migration like this:
1. I would not rely on the Excel URL directly
The URL in the Excel response is essentially a link to the stored file. It doesn't automatically give the HTTP action a usable binary download endpoint.
You can try an HTTP GET against the URL, but if the URL requires Microsoft 365 authentication, a normal HTTP action won't necessarily authenticate as the Form owner. Your browser works because you're already authenticated to Microsoft 365.
So this:
Excel URL → HTTP GET → SharePoint Image
is not something I'd consider a reliable/supported approach for this scenario.
2. The cleanest solution is still the owner's OneDrive connection
Your observation is correct: the file belongs to User X's OneDrive, and Forms stores uploaded files there.
If User X gives you access to the relevant Forms folder, you can use a OneDrive for Business connection that has access to that location.
You don't necessarily need User X to run the entire migration flow. The important part is that the connection used by the action retrieving the file must have permission to the actual file.
Then the pattern becomes:
Excel row
→ identify file
→ OneDrive Get file content
→ create/update SharePoint item
→ populate Image column
3. Another option I'd seriously consider: SharePoint Document Library
If this is a migration of historical profile pictures, I'd actually consider whether the SharePoint Image column is the best target.
You could:
Forms OneDrive
→ Get file content
→ SharePoint Create file
→ store the file in a document library
→ associate it with the migrated list item
This gives you the actual file as a SharePoint document and avoids some of the limitations around Image-column handling.
4. Don't confuse the browser URL with the file content
This is the key point I'd mention in the Community answer.
Your browser successfully opening the URL proves:
Your browser session has access to the file.
It does not prove:
Power Automate's HTTP action has permission to download the file.
Those are two different authentication contexts.
If you want to test the HTTP approach, use a single known image URL and inspect the HTTP action's response. If you get HTML/login content, 401, 403, or a redirect to Microsoft login, you've confirmed that the URL requires authenticated access.
What I'd recommend
For an existing/historical Forms migration, I would use the owner's OneDrive access rather than trying to reverse-engineer the Forms URL.
The fact that the Excel workbook is shared with you doesn't automatically mean the uploaded files have the same permissions. Microsoft specifically notes that Forms-uploaded files are stored separately in the owner's OneDrive/SharePoint storage.
So I'd build it as:
Excel → Parse image URL → Get file metadata/content from Form owner's OneDrive → SharePoint
If there are hundreds/thousands of images, I'd also avoid making the flow dependent on manually parsing the URL. Instead, locate the Forms upload folder (Apps/Microsoft Forms/<Form>/<Question>) and match the file using the filename/response data. Microsoft documents that uploaded files are stored in this Forms folder structure.
That will generally be much more robust for a one-time historical migration.
