unfortunately, file selector does not allow to load a list of filenames from MATLAB variables or .mat files. However, I could think of a number of ways to help you select the files:
* If all files have the same name, but live in different folders in your project (e.g. all con_0001.img files from all your subjects), then you could navigate to the top level of your project, enter ^con_0001\.img$ into the filter field and press the 'Rec' button. This will go through all folders and eventually collect all con_0001.img files that are found.
* If your files are spread in a more complicated way, you should consider the 'Save Batch and Script' option of the batch GUI. If you leave the 'Scans' items blank in the GUI, the script skeleton will allow to fill them using standard MATLAB commands. Note, that for the batch system file names are always cell arrays of strings.
Hope this helps,