gci c:Clients*footer.jpg |
   ?{($_.directory.name -match ''^d+-d+$') -and ($_.length -eq 4904)}

gci c:Clients*footer.jpg |
   ?{($_.directory.name -match '^d+-d+$') -and ($_.length -eq 4904)} |
       %{copy-item 'c:NewArtworkfooter.jpg' "$($_.directory)footer.jpg" -force}