You can insert files such as PDF's or Pictures into a container field. One of your options when inserting is "store by reference" which inserts the file path into the container field instead of copying the image.
"can I point to a directory that will show any file name that is the same number as the record number so that it only shows related files?"
Not with just filemaker, but there are file manipulation plug ins that can do this. If you have a windows system, check out Moo Plug as it has such features and is a free download.
"Also when in a table view that shows many records I would like a field indicating that there is a picture attached to the record line and then when the mouse it over or it is click a window will op up showing the picture. Is this possible?"
It's possible. You can even place a small "thumbnail" sized copy of the container field on you layout and set it up as a button that switches to a different layout where you have a large format copy of the container field. You can just switch layouts or use the new window command to pop up your picture in a new, separate window.
There are also ways to use a web viewer to display the contents of a file such as a picture or PDF and there's a third party add on you can look into called super container.
I need to play with this now.