Storing images in database for web applications

Hi all,

I'm wondering if anyone has experience of storing and getting images to and
from a database? We currently have the problem of images being uploaded to
a single gateway used by many companies, most of which run several
websites. As it stands, once they upload the image, it then has to be
fsync'd to the appropriate servers (3-way in some cases) or accessed through
our image proxy.

But now we wish to redesign our various image upload systems into one system
which will also make images available across various sites/companies and
therefore servers. So one solution is to store images in a database. What
I'm wondering is if this is an appropriate solution? What are the
downsides? Could we expect severe performance hits? To help mitigate the
issue of many sites continuously querying a database for images, we'd
implement a caching system, so images would only be queried from the
database probably around once an hour.

The benefits I can see is that images are managed in one place and
accessibly easily by all servers. The problem is putting everything in one
place (all eggs in one basket), so if the server goes down, all sites lose
their images once their cache has expired... unless we implemented a system
that falls back to cache if connection fails, even if cache has expired.

Any suggestion? Alternatives?

Thanks

Thom