[gthumb] tiff and tga support transparency as well

[Paolo Bacchilega <paobac src gnome org>]

commit 4b04341cfafe2ffc417caf1625fe0d70309cf258
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Wed Aug 10 10:08:48 2022 +0200

    tiff and tga support transparency as well

 gthumb/glib-utils.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/gthumb/glib-utils.c b/gthumb/glib-utils.c
index 760cace5..173f2da3 100644
--- a/gthumb/glib-utils.c
+++ b/gthumb/glib-utils.c
@@ -1921,7 +1921,9 @@ _g_mime_type_has_transparency (const char *mime_type)
                || (strcmp (mime_type, "image/jxl") == 0)
                || (strcmp (mime_type, "image/avif") == 0)
                || (strcmp (mime_type, "image/heif") == 0)
-               || (strcmp (mime_type, "image/heic") == 0);
+               || (strcmp (mime_type, "image/heic") == 0)
+               || (strcmp (mime_type, "image/tiff") == 0)
+               || (strcmp (mime_type, "image/x-tga") == 0);
 }