diff --git a/lib/Artwork.php b/lib/Artwork.php
index 7cb71a4a..9117e11c 100644
--- a/lib/Artwork.php
+++ b/lib/Artwork.php
@@ -72,17 +72,27 @@ class Artwork extends PropertiesBase{
 		return $this->_UrlName;
 	}
 
-	protected function GetSubmitter(): User{
+	protected function GetSubmitter(): ?User{
 		if($this->_Submitter === null){
-			$this->_Submitter = User::Get($this->SubmitterUserId);
+			try{
+				$this->_Submitter = User::Get($this->SubmitterUserId);
+			}
+			catch(Exceptions\InvalidUserException){
+				// Return null
+			}
 		}
 
 		return $this->_Submitter;
 	}
 
-	protected function GetReviewer(): User{
+	protected function GetReviewer(): ?User{
 		if($this->_Reviewer === null){
-			$this->_Reviewer = User::Get($this->ReviewerUserId);
+			try{
+				$this->_Reviewer = User::Get($this->ReviewerUserId);
+			}
+			catch(Exceptions\InvalidUserException){
+				// Return null
+			}
 		}
 
 		return $this->_Reviewer;
diff --git a/lib/Exceptions/InvalidLoginException.php b/lib/Exceptions/InvalidLoginException.php
new file mode 100644
index 00000000..cbc758f8
--- /dev/null
+++ b/lib/Exceptions/InvalidLoginException.php
@@ -0,0 +1,6 @@
+<?
+namespace Exceptions;
+
+class InvalidLoginException extends AppException{
+	protected $message = 'We couldn’t validate your login information.';
+}
diff --git a/lib/Exceptions/InvalidUserException.php b/lib/Exceptions/InvalidUserException.php
index 36818da3..b270a3ba 100644
--- a/lib/Exceptions/InvalidUserException.php
+++ b/lib/Exceptions/InvalidUserException.php
@@ -2,5 +2,5 @@
 namespace Exceptions;
 
 class InvalidUserException extends AppException{
-	protected $message = 'We couldn’t validate your login information.';
+	protected $message = 'We couldn’t locate that user.';
 }
diff --git a/lib/Session.php b/lib/Session.php
index 22706b08..e147ea84 100644
--- a/lib/Session.php
+++ b/lib/Session.php
@@ -1,4 +1,6 @@
 <?
+
+use Exceptions\InvalidLoginException;
 use Ramsey\Uuid\Uuid;
 use Safe\DateTime;
 use function Safe\strtotime;
@@ -33,33 +35,38 @@ class Session extends PropertiesBase{
 	// *******
 
 	public function Create(?string $email = null, ?string $password = null): void{
-		$this->User = User::GetIfRegistered($email, $password);
-		$this->UserId = $this->User->UserId;
+		try{
+			$this->User = User::GetIfRegistered($email, $password);
+			$this->UserId = $this->User->UserId;
 
-		$existingSessions = Db::Query('
-						SELECT SessionId,
-						       Created
-						from Sessions
-						where UserId = ?
-					', [$this->UserId]);
+			$existingSessions = Db::Query('
+							SELECT SessionId,
+							       Created
+							from Sessions
+							where UserId = ?
+						', [$this->UserId]);
 
-		if(sizeof($existingSessions) > 0){
-			$this->SessionId = $existingSessions[0]->SessionId;
-			$this->Created = $existingSessions[0]->Created;
+			if(sizeof($existingSessions) > 0){
+				$this->SessionId = $existingSessions[0]->SessionId;
+				$this->Created = $existingSessions[0]->Created;
+			}
+			else{
+				$uuid = Uuid::uuid4();
+				$this->SessionId = $uuid->toString();
+				$this->Created = new DateTime();
+				Db::Query('
+						INSERT into Sessions (UserId, SessionId, Created)
+						values (?,
+						        ?,
+						        ?)
+					', [$this->UserId, $this->SessionId, $this->Created]);
+			}
+
+			self::SetSessionCookie($this->SessionId);
 		}
-		else{
-			$uuid = Uuid::uuid4();
-			$this->SessionId = $uuid->toString();
-			$this->Created = new DateTime();
-			Db::Query('
-					INSERT into Sessions (UserId, SessionId, Created)
-					values (?,
-					        ?,
-					        ?)
-				', [$this->UserId, $this->SessionId, $this->Created]);
+		catch(Exceptions\InvalidUserException){
+			throw new InvalidLoginException();
 		}
-
-		self::SetSessionCookie($this->SessionId);
 	}
 
 	public static function GetLoggedInUser(): ?User{
diff --git a/lib/User.php b/lib/User.php
index dfba00f8..93046b26 100644
--- a/lib/User.php
+++ b/lib/User.php
@@ -114,6 +114,10 @@ class User extends PropertiesBase{
 	// ***********
 
 	public static function Get(?int $userId): User{
+		if($userId === null){
+			throw new Exceptions\InvalidUserException();
+		}
+
 		$result = Db::Query('
 					SELECT *
 					from Users
diff --git a/www/artworks/get.php b/www/artworks/get.php
index e1e91318..90c7f900 100644
--- a/www/artworks/get.php
+++ b/www/artworks/get.php
@@ -82,7 +82,7 @@ catch(Exceptions\ArtworkNotFoundException){
 			<? if($isAdminView){ ?>
 				<tr>
 					<td>Submitted by</td>
-					<td><? if($artwork->SubmitterUserId === null){ ?>Anonymous<? }else{ ?><a href="mailto:<?= Formatter::ToPlainText($artwork->Submitter->Email) ?>"><? if($artwork->Submitter->Name !== null){ ?> <?= Formatter::ToPlainText($artwork->Submitter->Name) ?><? }else{ ?><?= Formatter::ToPlainText($artwork->Submitter->Email) ?><? } ?></a><? } ?></td>
+					<td><? if($artwork->Submitter === null){ ?>Anonymous<? }else{ ?><a href="mailto:<?= Formatter::ToPlainText($artwork->Submitter->Email) ?>"><? if($artwork->Submitter->Name !== null){ ?> <?= Formatter::ToPlainText($artwork->Submitter->Name) ?><? }else{ ?><?= Formatter::ToPlainText($artwork->Submitter->Email) ?><? } ?></a><? } ?></td>
 				</tr>
 				<? if($artwork->Reviewer !== null){ ?>
 					<tr>