Hi

> I am about to add a potentially very large blob field to one of my
> tables for the storing of images for stock items.
>

Since you are adding a new feature it would definitely be more advisable to put images in a new table. That way you ensure you will not break any existing code or degrade performance.

>
> There will only ever be one image for each stock item, and images will
> never be shared amongst stock items.
>

Those kind of statements tend to prove false in time. If one image per stock is a requirement it is easy to put constraints into images table and make them 1-on-1 in reference to stock table. If later you decide you need more than one image you can remove constrint.

Sasha