Gimp: gimp apng loader heap-buffer-overflow when fctl width exceeds ihdr width (file-png.c)

A heap-buffer-overflow vulnerability exists in the APNG (Animated PNG) file loader of GIMP. This flaw occurs when the `fcTL` width exceeds the `IHDR` width, leading to pixel data being written past the end of a heap allocation. Additionally, a heap-based buffer overflow exists in the DDS plug-in due to a BPP mismatch in the `load_layer()` function. Both vulnerabilities can be triggered by opening a specially crafted image file, potentially leading to code execution.