Select "Mix Lines" in the resource, that way all the lines are mixed and thus it will have a random line. Or you can use javascript to mix the array list using function shuffle to get a better constant randomization. I believe there's also the option "Shuffle List" under the "List" option
Thank you! it worked, i was using [[VARIABLE]]/Images.txt with expression, it was also giving me error but then i used it with string then it worked. I thought in string, variables values cannot be used :)
