bash loop

for file in ./*.png; 
do
  if  grep -q ${file:2} ./fileslist.txt;
  then
    echo "skipping $file"
  else
    echo "moving $file"
    mv "$f" ./newdir
  fi
done

more efficent

while IFS="" read -r file || [ -n "$file" ]
do
  printf '%s\n' "$file"
  mv ./$file ./newdir/
done < fileslist.txt

more efficient and does what you want

# get list of files in current dir
printf '%s\n' *.png > current_dir_files.txt
# sort current dir files and files to exclude
sort current_dir_files.txt
sort filenames.txt
# save the filenames which exist in the current dir but not in the exclude list
comm -23 current_dir_files.txt filenames.txt > required_files.txt
# make newdir if it doesnt exist
mkdir -p ./newdir/
#loop through required files and move to newdir
while IFS="" read -r file || [ -n "$file" ]
do
  printf '%s\n' "$file"
  mv ./$file ./newdir/
done < required_files.txt