{
///////////////////////////////////////////////////////////////////////////////////////////////
// pick_random_file(directory,filter,attr)
///////////////////////////////////////////////////////////////////////////////////////////////
// returns a random file from the directory, filter and attributes you choose
///////////////////////////////////////////////////////////////////////////////////////////////
// argument0: directory: directory to search in (example: "D:My Documents:examplefolder")
///////////////////////////////////////////////////////////////////////////////////////////////
// argument1: filter: only search for the sepcified file extension (example: "jpg")
///////////////////////////////////////////////////////////////////////////////////////////////
// argument2: attr: search for the following optional files with special attributes too:
//// fa_readonly (read-only files), fa_hidden (hidden files), fa_sysfile (system files), 
//// fa_volumeid (volume-id files), fa_directory (directories), fa_archive (archived files)
//// (those are all constants, so if you type them right they will be colored red ;))
//// (example: fa_readonly+fa_sysfile+fa_archive)
///////////////////////////////////////////////////////////////////////////////////////////////

var dir,filt,attr,fnum,pickfile;

dir=argument0
filt=argument1
attr=argument2
fnum=0

file_find_first(dir+"*."+filt,attr)

while !(file_find_next()="")
    {
    fnum+=1
    }
file_find_close()

pickfile=round(random(fnum))

openfile=file_find_first(dir+"*."+filt,attr)

repeat(pickfile)
    {
    openfile=file_find_next()
    }
file_find_close()

return(openfile)
}