this will write the file name on to the png image

IMscript-png.sh

for img in *.png; do

   width=$(identify -format %W ${img})
   width=$(( ${width} * 9 / 10 ))

   convert                  \
     -background '#0008'    \
     -gravity center        \
     -fill white            \
     -size ${width}x100     \
      caption:"${img}"      \
      "${img}"              \
     +swap                  \
     -gravity south         \
     -composite             \
      "${img}"

done