Sort alphabetically

[snibgo]

The problem may be the drive "C:" in the file list. Try removing that, but ensure your current drive is "C:".

[gialandra]

Now the name of items in myimages.txt are:
\1\PNG\2x0x0.png
\1\PNG\2x0x1.png
...

C:\1>magick montage -tile 7x -geometry +0+0 @myimages.txt "C:\1\col.png"
montage: unable to open image 'ÿþ\': No such file or directory @ error/blob.c/OpenBlob/3485.
montage: no decode delegate for this image format `' @ error/constitute.c/ReadImage/556.
montage: `C:\1\col.png' @ error/montage.c/MontageImageCommand/1777.

C:\1>

[gialandra]

Finally I found the right powershell line to list in naturally order and in digestible txt format (snibgo had guessed):

@(Get-ChildItem -path C:\...\*.png | Sort-Object { [regex]::Replace($_.Name, '\d+', { $args[0].Value.PadLeft(20) }) }).fullname |out-file -encoding ASCII c:\...\myimages.txt

Thank you