Loading Image From DB

I'm storing images in a SQL DB as Base64 from a Web Core application. I can read these back in a VCL application using FireDAC by creating a JPEG and assigning it to an Image's Picture. I'm trying to read the same data back in a Web core application and cannot see the image, just a small graphic placeholder in the top left. Do I need to use a different approach ?

iz is a TWebImageZoomControl;

iz.URL := 'data:image/jpeg;base64,' + DataSet.FieldByName('Image').AsString;
iz.URLZoom := 'data:image/jpeg;base64,' + DataSet.FieldByName('Image').AsString;

Normally, I would expect this approach to work.
What is the exact full URL you assign? Can you check this URL separately? Did you inspect in the browser console if there are any errors?