Fixed bug, check if filename is set
Fixed bug, check if filename is set

jshoyer/plantcv,danforthcenter/plantcv,stiphyMT/plantcv,stiphyMT/plantcv,stiphyMT/plantcv,AntonSax/plantcv,AntonSax/plantcv,jshoyer/plantcv,danforthcenter/plantcv,danforthcenter/plantcv