Fix Fl_Image::fail() that reported always failure for Fl_Bitmap's.

src/Fl_Image.cxx

@@ -202,7 +202,7 @@ void Fl_Image::label(Fl_Menu_Item* m) {
 */
 int Fl_Image::fail() const {
   // if no image exists, ld_ may contain a simple error code
-  if ((w_ <= 0) || (h_ <= 0) || (d_ <= 0)) {
+  if ((w_ <= 0) || (h_ <= 0) || (d_ <= 0 && count_ == 0)) {
     if (ld_ == 0)
       return ERR_NO_IMAGE;
     else

test/gl_image.cxx

@@ -96,7 +96,7 @@ void chooser_cb(Fl_Widget *, Gl_Image_Window *mainwin) {
   char *fname = fl_file_chooser("select image file", "*.{png,jpg,gif,svg,svgz,xbm,xpm,ico}", NULL, 0);
   if (fname) {
     Fl_Shared_Image *shared = Fl_Shared_Image::get(fname);
-    if (shared && shared->w() && shared->h()) {
+    if (shared && !shared->fail()) {
       mainwin->copy_label(fname);
       mainwin->set_image(shared);
     }