$UserCredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/?proxyMethod=RPS -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session

#Update the user photos path here. Name of the file should be username of the Office365 user.
$path= 'C:\User images\'
$Images = Get-ChildItem $path
$Images |Foreach-Object{
$Identity = ($_.Name.Tostring() -split "\.")[0]
$PictureData = $path+$_.name
Set-UserPhoto -Identity $Identity -PictureData ([System.IO.File]::ReadAllBytes($PictureData)) -Confirm:$false }