diff --git a/src/Content/Text/BBCode.php b/src/Content/Text/BBCode.php
index cd433bdbb..ce6b36081 100644
--- a/src/Content/Text/BBCode.php
+++ b/src/Content/Text/BBCode.php
@@ -499,8 +499,8 @@ class BBCode
 				}
 
 				$i = $curlResult->getBody();
-				$type = $curlResult->getContentType();
-				$type = Images::getMimeTypeByData($i, $mtch[1], $type);
+				$contType = $curlResult->getContentType();
+				$type = Images::getMimeTypeByData($i, $mtch[1], $contType);
 
 				if ($i) {
 					$Image = new Image($i, $type);
diff --git a/src/Model/Photo.php b/src/Model/Photo.php
index a59c30aca..20d2c8a7a 100644
--- a/src/Model/Photo.php
+++ b/src/Model/Photo.php
@@ -492,16 +492,17 @@ class Photo
 		if (!empty($image_url)) {
 			$ret = DI::httpRequest()->get($image_url);
 			$img_str = $ret->getBody();
-			$type = $ret->getContentType();
+			$contType = $ret->getContentType();
 		} else {
 			$img_str = '';
+			$contType = [];
 		}
 
 		if ($quit_on_error && ($img_str == "")) {
 			return false;
 		}
 
-		$type = Images::getMimeTypeByData($img_str, $image_url, $type);
+		$type = Images::getMimeTypeByData($img_str, $image_url, $contType);
 
 		$Image = new Image($img_str, $type);
 		if ($Image->isValid()) {
diff --git a/src/Model/User.php b/src/Model/User.php
index 49423ce9e..48a13e6dd 100644
--- a/src/Model/User.php
+++ b/src/Model/User.php
@@ -1095,13 +1095,13 @@ class User
 			$curlResult = DI::httpRequest()->get($photo);
 			if ($curlResult->isSuccess()) {
 				$img_str = $curlResult->getBody();
-				$type = $curlResult->getContentType();
+				$contType = $curlResult->getContentType();
 			} else {
 				$img_str = '';
-				$type = '';
+				$contType = [];
 			}
 
-			$type = Images::getMimeTypeByData($img_str, $photo, $type);
+			$type = Images::getMimeTypeByData($img_str, $photo, $contType);
 
 			$Image = new Image($img_str, $type);
 			if ($Image->isValid()) {
diff --git a/src/Network/CurlResult.php b/src/Network/CurlResult.php
index 65c110338..1c74634db 100644
--- a/src/Network/CurlResult.php
+++ b/src/Network/CurlResult.php
@@ -245,7 +245,7 @@ class CurlResult implements IHTTPResult
 	public function getHeader($header)
 	{
 		if (empty($header)) {
-			return '';
+			return [];
 		}
 
 		$header = strtolower(trim($header));
@@ -256,7 +256,7 @@ class CurlResult implements IHTTPResult
 			return $headers[$header];
 		}
 
-		return '';
+		return [];
 	}
 
 	/** {@inheritDoc} */
@@ -289,7 +289,11 @@ class CurlResult implements IHTTPResult
 			$parts = explode(':', $line);
 			$headerfield = strtolower(trim(array_shift($parts)));
 			$headerdata = trim(implode(':', $parts));
-			$this->header_fields[$headerfield] = $headerdata;
+			if (empty($this->header_fields[$headerfield])) {
+				$this->header_fields[$headerfield] = [$headerdata];
+			} elseif (!in_array($headerdata, $this->header_fields[$headerfield])) {
+				$this->header_fields[$headerfield][] = $headerdata;
+			}
 		}
 
 		return $this->header_fields;
diff --git a/src/Network/IHTTPResult.php b/src/Network/IHTTPResult.php
index 77ee86976..acee2dde9 100644
--- a/src/Network/IHTTPResult.php
+++ b/src/Network/IHTTPResult.php
@@ -19,7 +19,7 @@ interface IHTTPResult
 	/**
 	 * Returns the Content Type
 	 *
-	 * @return string the Content Type
+	 * @return string[] the Content Types
 	 */
 	public function getContentType();
 
@@ -29,7 +29,7 @@ interface IHTTPResult
 	 *
 	 * @param string $header optional header field. Return all fields if empty
 	 *
-	 * @return string the headers or the specified content of the header variable
+	 * @return string[] the headers or the specified content of the header variable
 	 */
 	public function getHeader($header);
 
diff --git a/src/Network/Probe.php b/src/Network/Probe.php
index 111580800..ef899b6c1 100644
--- a/src/Network/Probe.php
+++ b/src/Network/Probe.php
@@ -430,7 +430,7 @@ class Probe
 		}
 
 		// If it isn't a HTML file then exit
-		if (($curlResult->getContentType() != '') && !strstr(strtolower($curlResult->getContentType()), 'html')) {
+		if (!in_array('html', $curlResult->getContentType())) {
 			return false;
 		}
 
diff --git a/src/Protocol/OStatus.php b/src/Protocol/OStatus.php
index 8d818471b..215c08fa0 100644
--- a/src/Protocol/OStatus.php
+++ b/src/Protocol/OStatus.php
@@ -736,7 +736,7 @@ class OStatus
 		$xml = '';
 
 		if ($curlResult->inHeader('Content-Type') &&
-			stristr($curlResult->getHeader('Content-Type'), 'application/atom+xml')) {
+			in_array('application/atom+xml', $curlResult->getHeader('Content-Type'))) {
 			$xml = $curlResult->getBody();
 		}
 
@@ -930,7 +930,7 @@ class OStatus
 		$xml = '';
 
 		if ($curlResult->inHeader('Content-Type') &&
-			stristr($curlResult->getHeader('Content-Type'), 'application/atom+xml')) {
+			in_array('application/atom+xml', $curlResult->getHeader('Content-Type'))) {
 			Logger::log('Directly fetched XML for URI ' . $related_uri, Logger::DEBUG);
 			$xml = $curlResult->getBody();
 		}
diff --git a/src/Util/Images.php b/src/Util/Images.php
index bf84ee6c2..c1ac731b6 100644
--- a/src/Util/Images.php
+++ b/src/Util/Images.php
@@ -75,23 +75,25 @@ class Images
 	/**
 	 * Fetch image mimetype from the image data or guessing from the file name
 	 *
-	 * @param string $image_data Image data
-	 * @param string $filename   File name (for guessing the type via the extension)
-	 * @param string $mime       default mime type
+	 * @param string   $image_data Image data
+	 * @param string   $filename   File name (for guessing the type via the extension)
+	 * @param string[] $mimeTypes  possible mime types
 	 *
 	 * @return string
 	 * @throws \Exception
 	 */
-	public static function getMimeTypeByData(string $image_data, string $filename = '', string $mime = '')
+	public static function getMimeTypeByData(string $image_data, string $filename = '', array $mimeTypes = [])
 	{
-		if (substr($mime, 0, 6) == 'image/') {
-			Logger::info('Using default mime type', ['filename' => $filename, 'mime' => $mime]);
-			return $mime;
+		foreach ($mimeTypes as $mimeType) {
+			if (substr($mimeType, 0, 6) == 'image/') {
+				Logger::info('Using default mime type', ['filename' => $filename, 'mime' => $mimeTypes]);
+				return $mimeType;
+			}
 		}
 
 		$image = @getimagesizefromstring($image_data);
 		if (!empty($image['mime'])) {
-			Logger::info('Mime type detected via data', ['filename' => $filename, 'default' => $mime, 'mime' => $image['mime']]);
+			Logger::info('Mime type detected via data', ['filename' => $filename, 'default' => $mimeTypes, 'mime' => $image['mime']]);
 			return $image['mime'];
 		}
 
diff --git a/src/Util/ParseUrl.php b/src/Util/ParseUrl.php
index d95897b1d..79c3928d7 100644
--- a/src/Util/ParseUrl.php
+++ b/src/Util/ParseUrl.php
@@ -272,8 +272,10 @@ class ParseUrl
 		$charset = '';
 		// Look for a charset, first in headers
 		// Expected form: Content-Type: text/html; charset=ISO-8859-4
-		if (preg_match('/charset=([a-z0-9-_.\/]+)/i', $curlResult->getContentType(), $matches)) {
-			$charset = trim(trim(trim(array_pop($matches)), ';,'));
+		foreach ($curlResult->getContentType() as $type) {
+			if (preg_match('/charset=([a-z0-9-_.\/]+)/i', $type, $matches)) {
+				$charset = trim(trim(trim(array_pop($matches)), ';,'));
+			}
 		}
 
 		// Then in body that gets precedence
diff --git a/tests/datasets/curl/about.head.php b/tests/datasets/curl/about.head.php
index d0be0feb4..b7773b81a 100644
--- a/tests/datasets/curl/about.head.php
+++ b/tests/datasets/curl/about.head.php
@@ -1,20 +1,20 @@
 <?php
 
 return [
-	'http/2 200' => '',
-    'date' => 'Thu, 11 Oct 2018 18:43:54 GMT',
-    'content-type' => 'text/html; charset=utf-8',
-    'vary' => 'Accept-Encoding',
-    'server' => 'Mastodon',
-    'x-frame-options' => 'SAMEORIGIN',
-    'x-content-type-options' => 'nosniff',
-    'x-xss-protection' => '1; mode=block',
-    'etag' => 'W/"706e6c48957e1d46ecf9d7597a7880af"',
-    'cache-control' => 'max-age=0, private, must-revalidate',
-    'set-cookie' => '_mastodon_session=v3kcy%2FW3aZYBBvZUohuwksEKwzYIyEUlEuJ1KqTAfWPKvVQq%2F4UuJ39zp621VyfpQNlvY46TL%2FYutzXowSLYQBNFCJcrEiF04aU0TdtHls9zynMiyeHhoVgCijOXWXNt9%2FCmpQ49RkNEujkv9NaJ0cum32MCVZKjE9%2BMKmLM%2F8ZygZeLBGJ7sg%3D%3D--QGIiU0%2FpXc3Aym8F--he2iRRPePOdtEs3z%2BufSXg%3D%3D; path=/; secure; HttpOnly',
-    'x-request-id' => 'a0c0b8e7-cd60-4efa-b79b-cf1b0d5a0784',
-    'x-runtime' => '0.049566',
-    'strict-transport-security' => 'max-age=31536000; includeSubDomains; preload',
-    'referrer-policy' => 'same-origin',
-    'content-security-policy' => "frame-ancestors 'none'; script-src 'self'; object-src 'self'; img-src * data: blob:; media-src 'self' data:; font-src 'self' data: https://fonts.gstatic.com/; connect-src 'self' blob: wss://mastodonten.de",
+	'http/2 200' => [''],
+    'date' => ['Thu, 11 Oct 2018 18:43:54 GMT'],
+    'content-type' => ['text/html; charset=utf-8'],
+    'vary' => ['Accept-Encoding'],
+    'server' => ['Mastodon'],
+    'x-frame-options' => ['DENY', 'SAMEORIGIN'],
+    'x-content-type-options' => ['nosniff'],
+    'x-xss-protection' => ['1; mode=block'],
+    'etag' => ['W/"706e6c48957e1d46ecf9d7597a7880af"'],
+    'cache-control' => ['max-age=0, private, must-revalidate'],
+    'set-cookie' => ['_mastodon_session=v3kcy%2FW3aZYBBvZUohuwksEKwzYIyEUlEuJ1KqTAfWPKvVQq%2F4UuJ39zp621VyfpQNlvY46TL%2FYutzXowSLYQBNFCJcrEiF04aU0TdtHls9zynMiyeHhoVgCijOXWXNt9%2FCmpQ49RkNEujkv9NaJ0cum32MCVZKjE9%2BMKmLM%2F8ZygZeLBGJ7sg%3D%3D--QGIiU0%2FpXc3Aym8F--he2iRRPePOdtEs3z%2BufSXg%3D%3D; path=/; secure; HttpOnly'],
+    'x-request-id' => ['a0c0b8e7-cd60-4efa-b79b-cf1b0d5a0784'],
+    'x-runtime' => ['0.049566'],
+    'strict-transport-security' => ['max-age=31536000; includeSubDomains; preload'],
+    'referrer-policy' => ['same-origin'],
+    'content-security-policy' => ["frame-ancestors 'none'; script-src 'self'; object-src 'self'; img-src * data: blob:; media-src 'self' data:; font-src 'self' data: https://fonts.gstatic.com/; connect-src 'self' blob: wss://mastodonten.de"],
 ];
diff --git a/tests/datasets/curl/about.redirect.php b/tests/datasets/curl/about.redirect.php
index 5ae3fd88f..f01689aad 100644
--- a/tests/datasets/curl/about.redirect.php
+++ b/tests/datasets/curl/about.redirect.php
@@ -1,21 +1,21 @@
 <?php
 
 return [
-	'http/2 301' => '',
-    'date' => 'Thu, 11 Oct 2018 18:43:54 GMT',
-    'content-type' => 'text/html; charset=utf-8',
-    'vary' => 'Accept-Encoding',
-    'server' => 'Mastodon',
-    'location' => 'https://test.other/some/',
-    'x-frame-options' => 'SAMEORIGIN',
-    'x-content-type-options' => 'nosniff',
-    'x-xss-protection' => '1; mode=block',
-    'etag' => 'W/"706e6c48957e1d46ecf9d7597a7880af"',
-    'cache-control' => 'max-age=0, private, must-revalidate',
-    'set-cookie' => '_mastodon_session=v3kcy%2FW3aZYBBvZUohuwksEKwzYIyEUlEuJ1KqTAfWPKvVQq%2F4UuJ39zp621VyfpQNlvY46TL%2FYutzXowSLYQBNFCJcrEiF04aU0TdtHls9zynMiyeHhoVgCijOXWXNt9%2FCmpQ49RkNEujkv9NaJ0cum32MCVZKjE9%2BMKmLM%2F8ZygZeLBGJ7sg%3D%3D--QGIiU0%2FpXc3Aym8F--he2iRRPePOdtEs3z%2BufSXg%3D%3D; path=/; secure; HttpOnly',
-    'x-request-id' => 'a0c0b8e7-cd60-4efa-b79b-cf1b0d5a0784',
-    'x-runtime' => '0.049566',
-    'strict-transport-security' => 'max-age=31536000; includeSubDomains; preload',
-    'referrer-policy' => 'same-origin',
-    'content-security-policy' => "frame-ancestors 'none'; script-src 'self'; object-src 'self'; img-src * data: blob:; media-src 'self' data:; font-src 'self' data: https://fonts.gstatic.com/; connect-src 'self' blob: wss://mastodonten.de",
+	'http/2 301' => [''],
+    'date' => ['Thu, 11 Oct 2018 18:43:54 GMT'],
+    'content-type' => ['text/html; charset=utf-8'],
+    'vary' => ['Accept-Encoding'],
+    'server' => ['Mastodon'],
+    'location' => ['https://test.other/some/'],
+    'x-frame-options' => ['DENY', 'SAMEORIGIN'],
+    'x-content-type-options' => ['nosniff'],
+    'x-xss-protection' => ['1; mode=block'],
+    'etag' => ['W/"706e6c48957e1d46ecf9d7597a7880af"'],
+    'cache-control' => ['max-age=0, private, must-revalidate'],
+    'set-cookie' => ['_mastodon_session=v3kcy%2FW3aZYBBvZUohuwksEKwzYIyEUlEuJ1KqTAfWPKvVQq%2F4UuJ39zp621VyfpQNlvY46TL%2FYutzXowSLYQBNFCJcrEiF04aU0TdtHls9zynMiyeHhoVgCijOXWXNt9%2FCmpQ49RkNEujkv9NaJ0cum32MCVZKjE9%2BMKmLM%2F8ZygZeLBGJ7sg%3D%3D--QGIiU0%2FpXc3Aym8F--he2iRRPePOdtEs3z%2BufSXg%3D%3D; path=/; secure; HttpOnly'],
+    'x-request-id' => ['a0c0b8e7-cd60-4efa-b79b-cf1b0d5a0784'],
+    'x-runtime' => ['0.049566'],
+    'strict-transport-security' => ['max-age=31536000; includeSubDomains; preload'],
+    'referrer-policy' => ['same-origin'],
+    'content-security-policy' => ["frame-ancestors 'none'; script-src 'self'; object-src 'self'; img-src * data: blob:; media-src 'self' data:; font-src 'self' data: https://fonts.gstatic.com/; connect-src 'self' blob: wss://mastodonten.de"],
 ];