[libgxps] images: check the extension in lower case

[Ignacio Casal Quinteiro <icq src gnome org>]

commit cf8fef812409ab152e332e3ba5630f73c80a5a96
Author: Ignacio Casal Quinteiro <qignacio amazon com>
Date:   Mon Jan 9 10:08:31 2017 +0100

    images: check the extension in lower case

 libgxps/gxps-images.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)
---
diff --git a/libgxps/gxps-images.c b/libgxps/gxps-images.c
index cef2338..82de3c5 100644
--- a/libgxps/gxps-images.c
+++ b/libgxps/gxps-images.c
@@ -903,22 +903,27 @@ gxps_images_get_image (GXPSArchive *zip,
                       GError     **error)
 {
        GXPSImage *image = NULL;
+       gchar *image_uri_lower;
 
        /* First try with extensions,
         * as it's recommended by the spec
         * (2.1.5 Image Parts)
         */
-       if (g_str_has_suffix (image_uri, ".png")) {
+       image_uri_lower = g_utf8_strdown (image_uri, -1);
+       if (g_str_has_suffix (image_uri_lower, ".png")) {
                image = gxps_images_create_from_png (zip, image_uri, error);
-       } else if (g_str_has_suffix (image_uri, ".jpg")) {
+       } else if (g_str_has_suffix (image_uri_lower, ".jpg")) {
                image = gxps_images_create_from_jpeg (zip, image_uri, error);
-       } else if (g_str_has_suffix (image_uri, ".tif")) {
+       } else if (g_str_has_suffix (image_uri_lower, ".tif")) {
                image = gxps_images_create_from_tiff (zip, image_uri, error);
-       } else if (g_str_has_suffix (image_uri, "wdp")) {
+       } else if (g_str_has_suffix (image_uri_lower, "wdp")) {
                GXPS_DEBUG (g_message ("Unsupported image format windows media photo"));
+               g_free (image_uri_lower);
                return NULL;
        }
 
+       g_free (image_uri_lower);
+
        if (!image) {
                gchar *mime_type;