The biggest drawback I've seen with storing images in a DB is that the image is never cached in the visitor's browser. To them, it's a new image, and a full new request for that image every single time. So where normally a cached image can be displayed without actually transferring the bytes on every request, an image sourced from a query will need to download fully every single time.
This has the effect of sucking bandwidth like there's no tomorrow! :p
Hey if anyone has any magic that can alleviate this issue, please lemme know, eh?