How can I output a list of filenames surrounded by quotation marks?

You can use FOR /F to run the DIR command and surround the output with quotes:

This is from the prompt

for /f "delims=" %A in ('dir /b /od *.png') do @echo "%A"

In a batch script, you would double the percent signs, so %A becomes %%A in both places.

A way using PowerShell:

(dir *.png | sort creationTime | % {"`"$($_.name)`""}) >>files.txt

• Filter *.png using Get-ChildItem.
• Sort them by CreationTime.
• Add double quotes to their names using Foreach loop
• Then write them to files.txt using operator.