Alamofire downloading multiple images using swift 3 - ios

Question

I currently have a an array of strings that contain about three thousand urls to download images. I have set up the following function to the pass the array of urls into:
func downloadAllImages(urlArray:[String])->Void{
var urlArray = urlArray
let destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)
var TotalProducts = urlArray.count
for i in 0 ..< urlArray.count {
Alamofire.download(
urlArray[i],
method: .get,
to: destination).downloadProgress(closure: { (progress) in
self.IndividualImage.text="\(progress.fractionCompleted*100)%"
}).response(completionHandler: { (DefaultDownloadResponse) in
TotalProducts-=1
self.DownloadLabel.text="Images left to download: \(TotalProducts)"
print("\(DefaultDownloadResponse.error)")
print("\(DefaultDownloadResponse.response)")
})
}
}
This works fine except it tends to cut out after downloading between 800-900 images and just stops. It outputs no errors. As I'm looping through every url and creating a task I imagine there are only so many concurrent tasks I can have at once. Any ideas?
UPDATE
I have gone through the output responses and found many are timing out:
Optional(Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={NSUnderlyingError=0x60800145b840 {Error Domain=kCFErrorDomainCFNetwork Code=-1001 "(null)" UserInfo={_kCFStreamErrorCodeKey=-2102, _kCFStreamErrorDomainKey=4}}, NSErrorFailingURLStringKey=www.MYURL.com/image1.jpg, NSErrorFailingURLKey=www.MYURL.com/image1.jpg, _kCFStreamErrorDomainKey=4, _kCFStreamErrorCodeKey=-2102, NSLocalizedDescription=The request timed out.})
So this is obvious as the for loop is sending everything to a task at once virtually and then it can only process so many at once. So the answer is to send them in batches. But how would I send a batch of 50 and then wait till every task has completed and then send another wave?