How to create your own Texture Fill

The above might be trivial but I don't know how to do it. Basically, I'd like to scan a texture (from a JPG image), insert it into the Texture Fill Dialogue i.e. Fill Tool --> Texture Fill, and then use it to fill objects. Anybody knows how to do it? Thank you.

you need to use pattern fill instead :-) fill tool->pattern fill and in that dialog you can see "load" button just bottom to the texture image :-)