ls: Cannot read '*.png': the file or the directory doesn't exist

ls -R | grep '.png$'

ls -R | grep .png$

find [startingPath] -type [fileType] -regex "[regularExpression]"

find . -type f -regex ".*.pdf"

find . -type f -regex ".*.pdf" -ls

find . -type f -regex ".*.pdf" -exec file {} ;

picture1.png
picture2.png

ls -R picture1.png picture2.png

ls -R *.png

shopt -s globstar
ls **/*.png

shopt -u globstar

globstar
    If set, the pattern ** used in a pathname expansion context will
    match all files and zero or more directories and subdirectories.
    If the pattern is followed by a /, only directories and
    subdirectories match.