Move all png files in folder to Trash

I use the following bash script to move all png files to Trash,but some how it does not delete png files with only one character in its name like "a.png"


#!/usr/bin/env bash

mv ~/Desktop/screenshots/*.png ~/.Trash 2> /dev/null
if [ $? -eq 0 ]; then
    echo "Files moved to Trash"
    echo "No Files to delete"

Any suggestions how to fix this ?

Got it working with AppleScript.
Using an applescript to get a list of png files and delete each file from the list

files of folder folderPath whose name extension is "png"