diff --git a/core/modules/responsive_image/responsive_image.module b/core/modules/responsive_image/responsive_image.module
index 39505a4..4b3b320 100644
--- a/core/modules/responsive_image/responsive_image.module
+++ b/core/modules/responsive_image/responsive_image.module
@@ -212,7 +212,7 @@ function theme_responsive_image($variables) {
           case 'sizes':
             foreach (array_filter($mapping_definition['sizes_image_styles']) as $image_style_name) {
               $dimensions = responsive_image_get_image_dimensions($image_style_name, array('width' => $variables['width'], 'height' => $variables['height']));
-              // Get mime type.
+              // Get MIME type.
               $derivative_mime_type = responsive_image_get_mime_type($image_style_name, $mime_type);
               $derivative_mime_types[] = $derivative_mime_type;
 
@@ -221,7 +221,7 @@ function theme_responsive_image($variables) {
             }
             break;
           case 'image_style':
-            // Get mime type.
+            // Get MIME type.
             $derivative_mime_type = responsive_image_get_mime_type($mapping_definition['image_style'], $mime_type);
             $derivative_mime_types[] = $derivative_mime_type;
 
@@ -229,7 +229,7 @@ function theme_responsive_image($variables) {
             break;
         }
       }
-      // Only add mime type if it is unique.
+      // Only add MIME type if it is unique.
       $derivative_mime_types = array_unique($derivative_mime_types);
 
       $sources[] = array(
@@ -281,7 +281,7 @@ function theme_responsive_image($variables) {
  *   - media: The media query to use.
  *   - srcset: The srcset containing the the path of the image file or a full
  *     URL and optionally multipliers.
- *   - mime_type: The mime type of the image (if known).
+ *   - mime_type: The MIME type of the image (if known).
  *   - sizes: The sizes attribute for the source element.
  *
  * @ingroup themeable
@@ -332,15 +332,15 @@ function responsive_image_get_image_dimensions($image_style_name, $dimensions) {
 }
 
 /**
- * Determines the mime type of an image.
+ * Determines the MIME type of an image.
  *
  * @param $image_style_name
  *   The image style that will be applied to the image.
  * @param $mime_type
- *   The original mime type of the image.
+ *   The original MIME type of the image.
  *
  * @return string
- *   The mime type of the image after the image style is applied.
+ *   The MIME type of the image after the image style is applied.
  */
 function responsive_image_get_mime_type($image_style_name, $mime_type) {
   if ($image_style_name == RESPONSIVE_IMAGE_EMPTY_IMAGE) {