I had a tool that did not write EXIF data to jpg files so I wrote this small Powershell script to use the file names that were conveniently creation dates in unix millisecond timestamps.

fix-creation-time.ps1

Add-Type -AssemblyName System.Drawing

$imageSourcePath = Get-Location
$files = Get-ChildItem -Path $imageSourcePath -filter *.jpg
$numFiles = $files.Count
[Int32]$counter = 0

foreach ($file in $files) {

	$takenDateUNIXMilli = $file.BaseName
	$takenDate = ((Get-Date 01.01.1970) + ([System.TimeSpan]::frommilliseconds($takenDateUNIXMilli)))
	$counter++

	Write-Progress "$numFiles image files." -PercentComplete (100 * $counter / $numFiles)

	$file.CreationTime = $takenDate
	$file.LastWriteTime = $takenDate
} 

Write-Output "Fixed CreationTime and LastWriteTime for $numFiles files from $imageSourcePath"