Adding Textures

I wish to add my own textures to the Texture/Texturizer drop down window so that they appear together with Snadstone, Bulap, Canvas, etc. I do not want to use the Load texture, Browse for folder, system as its too fiddly to fit into my actions method of working.
Can I add to the preset textures mentioned above ?
If Yes, what is the folder name/ address, and is there a particular method of installing my textures or do I just drag and drop?

Just select a portion of your image with the Rectangular Marquee; then pull down "Edit > Define Pattern". The new sample appears in your pattern maker.