Pillow `GdImageFile._open()`: image dimensions accepted without `_decompression_bomb_check()`

Description PIL/GdImageFile.py GdImageFile.open reads image dimensions from the GD 2.x header and stores them in self.size without calling Image.decompressionbombcheck. Because GdImageFile is not registered with Image.registeropen, it never passes through the standard Image.open code path that...