Clean up images in a folder, moving them to subfolders named YYYY-MM based on the image's creation date.

cleanup.ps1

$screenshotsDir = "$($env:userprofile)\OneDrive\Pictures\Screenshots"

$fileType = "png"

$images = Get-ChildItem -Path $screenshotsDir -filter "*.$fileType"

for ($i=0; $i -lt $images.Length; $i++) {
    $monthYearString = $images[$i].CreationTime.Year.ToString() + "-" + $images[$i].CreationTime.Month.ToString().PadLeft(2,"0")
    $folder = Join-Path $screenshotsDir $monthYearString
    if (-not (Test-Path -Path $folder -PathType Container)) {
        # Creating path
        New-Item -Path $folder -ItemType Directory
    }
    Move-Item $images[$i].FullName $folder
}

Or this one for Dropbox\Camera Uploads:

$years = 2012..2024
$months = 1..12

foreach ($year in $years) {
    foreach ($month in $months) {
        $monthnice = $month.ToString().PadLeft(2,"0")
        $str = "$year-$monthnice"
        if (-not (Test-Path -Path $str -PathType Container)) { New-Item -Path $str -ItemType Directory }
        Get-ChildItem "$str*" -File | % { Move-Item $_ $str }
    }
}