Fix: bitmaps with BITMAPV3INFOHEADER cannot be imported

These files are reportedly written by Photoshop and based on
a specification by Microsoft. More information can be found here:

https://en.wikipedia.org/wiki/BMP_file_format#DIB_header_(bitmap_information_header)
https://formats.kaitai.io/bmp/
https://web.archive.org/web/20150127132443/https://forums.adobe.com/message/3272950

Author: Gymnasiast

ext/gd/libgd/bmp.h

@@ -28,6 +28,7 @@ extern "C" {
 #define BMP_WINDOWS_V3 40
 #define BMP_OS2_V1 12
 #define BMP_OS2_V2 64
+#define BMP_WINDOWS_V3INFO 56
 #define BMP_WINDOWS_V4 108
 #define BMP_WINDOWS_V5 124
 

ext/gd/libgd/gd_bmp.c

@@ -545,6 +545,7 @@ static int bmp_read_info(gdIOCtx *infile, bmp_info_t *info)
 	switch (info->len) {
 		/* For now treat Windows v4 + v5 as v3 */
 	case BMP_WINDOWS_V3:
+	case BMP_WINDOWS_V3INFO:
 	case BMP_WINDOWS_V4:
 	case BMP_WINDOWS_V5:
 		BMP_DEBUG(printf("Reading Windows Header\n"));
@@ -685,8 +686,12 @@ static int bmp_read_direct(gdImagePtr im, gdIOCtxPtr infile, bmp_info_t *info, b
 			BMP_DEBUG(printf("Bitfield compression isn't supported for 24-bit\n"));
 			return 1;
 		}
-		BMP_DEBUG(printf("Currently no bitfield support\n"));
-		return 1;
+		/* For 32 BPP images, the bitfields do not contain any useful information. They can be safely skipped. */
+		if (info->depth != 32) {
+			BMP_DEBUG(printf("Currently no bitfield support\n"));
+			return 1;
+		}
+
 		break;
 
 	case BMP_BI_RLE8: