Accessing file using a built directory path

Hello,

I'm about to finish a Max application, and I would like the user to have a "start configuration" file for the patch.
This start configuration file will access several samples, and some pictures, that will be given with the application.
I would like to be sure the preset can be loaded whatever the directory used for locating the application, as long as the user keeps unchanged the directory tree at this point (user copies the application + a "Picture" folder + a "Sample" folder in the same location, whatever the location).
So I would like to :
1. Check the path of the Max application (ok, I found out)
2. Add to this path something like "/Picture" to build the good path to access the pictures
3. Access the files (ok using folder + umenu)

I do not know how to built the path ; how to add "/Picture", and send it to "folder $1 --> umenu" for example.
When I try "to symbol" to concatenate the two messages (1. application path and 2. remaining part of the path, to add), the resulting path has brackets as first and last character, and I do not know how to remove them.

Can you help ?

Thank you !