diff --git a/lib/private/legacy/OC_Image.php b/lib/private/legacy/OC_Image.php
index e6a815a3cf7..1b1d98325ba 100644
--- a/lib/private/legacy/OC_Image.php
+++ b/lib/private/legacy/OC_Image.php
@@ -124,7 +124,11 @@ class OC_Image implements \OCP\IImage {
 	 * @return int
 	 */
 	public function width() {
-		return $this->valid() ? imagesx($this->resource) : -1;
+		if ($this->valid() && (($width = imagesx($this->resource)) !== false)) {
+			return $width;
+		} else {
+			return -1;
+		}
 	}
 
 	/**
@@ -133,7 +137,11 @@ class OC_Image implements \OCP\IImage {
 	 * @return int
 	 */
 	public function height() {
-		return $this->valid() ? imagesy($this->resource) : -1;
+		if ($this->valid() && (($height = imagesy($this->resource)) !== false)) {
+			return $height;
+		} else {
+			return -1;
+		}
 	}
 
 	/**
diff --git a/lib/public/IImage.php b/lib/public/IImage.php
index 9d2b31e0e28..659cd24720d 100644
--- a/lib/public/IImage.php
+++ b/lib/public/IImage.php
@@ -98,7 +98,7 @@ interface IImage {
 	public function save($filePath = null, $mimeType = null);
 
 	/**
-	 * @return resource|\GdImage Returns the image resource in any.
+	 * @return false|resource|\GdImage Returns the image resource if any
 	 * @since 8.1.0
 	 */
 	public function resource();