diff --git a/src/file_psb.c b/src/file_psb.c
index e4f2ce71..5194a38c 100644
--- a/src/file_psb.c
+++ b/src/file_psb.c
@@ -52,6 +52,17 @@ const file_hint_t file_hint_psb= {
 
 static const unsigned char psb_header[6]={'8', 'B', 'P', 'S', 0x00, 0x02};
 static uint64_t psb_image_data_size_max=0;
+struct psb_file_header
+{
+  char signature[4];
+  uint16_t version;	/* must be 2 */
+  char reserved[6];	/* must be 0 */
+  uint16_t channels;	/* between 1 and 56 */
+  uint32_t height;	/* max of 300,000 */
+  uint32_t width;	/* max of 300,000 */
+  uint16_t depth;	/* 1, 8, 16 or 32 */
+  uint16_t color_mode;	/* Bitmap = 0; Grayscale = 1; Indexed = 2; RGB = 3; CMYK = 4; Multichannel = 7; Duotone = 8; Lab = 9 */
+} __attribute__ ((__packed__));
 
 static void register_header_check_psb(file_stat_t *file_stat)
 {
@@ -126,10 +137,8 @@ static int psb_skip_image_resources(const unsigned char *buffer, const unsigned
 
 static int psb_skip_color_mode(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
 {
-  psb_image_data_size_max=(buffer[buffer_size/2+12]<<8 | buffer[buffer_size/2+13]) *
-    (buffer[buffer_size/2+14]<<24 | buffer[buffer_size/2+15] <<16 | buffer[buffer_size/2+16]<<8 | buffer[buffer_size/2+17]) *
-    (buffer[buffer_size/2+18]<<24 | buffer[buffer_size/2+19] <<16 | buffer[buffer_size/2+20]<<8 | buffer[buffer_size/2+21]) *
-    buffer[buffer_size/2+23] / 8;
+  const struct psb_file_header *psb=(const struct psb_file_header *)&buffer[buffer_size/2];
+  psb_image_data_size_max=(uint64_t)le16(psb->channels) * le32(psb->height) * le32(psb->width) * le16(psb->depth) / 8;
 #ifdef DEBUG_PSD
   log_info("psb_image_data_size_max %lu\n", (long unsigned)psb_image_data_size_max);
 #endif
diff --git a/src/file_psd.c b/src/file_psd.c
index 357c81eb..83e8be67 100644
--- a/src/file_psd.c
+++ b/src/file_psd.c
@@ -50,28 +50,30 @@ const file_hint_t file_hint_psd= {
   .register_header_check=&register_header_check_psd
 };
 
-static const unsigned char psd_header[6]={'8', 'B', 'P', 'S', 0x00, 0x01};
 static uint64_t psd_image_data_size_max=0;
 
-static void register_header_check_psd(file_stat_t *file_stat)
+struct psd_file_header
 {
-  register_header_check(0, psd_header,sizeof(psd_header), &header_check_psd, file_stat);
-}
+  char signature[4];
+  uint16_t version;	/* must be 1 */
+  char reserved[6];	/* must be 0 */
+  uint16_t channels;	/* between 1 and 56 */
+  uint32_t height;	/* max of 30,000 */
+  uint32_t width;	/* max of 30,000 */
+  uint16_t depth;	/* 1, 8, 16 or 32 */
+  uint16_t color_mode;	/* Bitmap = 0; Grayscale = 1; Indexed = 2; RGB = 3; CMYK = 4; Multichannel = 7; Duotone = 8; Lab = 9 */
+} __attribute__ ((__packed__));
 
 static int header_check_psd(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
 {
-  if(memcmp(buffer,psd_header,sizeof(psd_header))==0)
-  {
-    reset_file_recovery(file_recovery_new);
-    file_recovery_new->min_filesize=70;
-    file_recovery_new->extension=file_hint_psd.extension;
-    /* File header */
-    file_recovery_new->calculated_file_size=0x1a;
-    file_recovery_new->data_check=&psd_skip_color_mode;
-    file_recovery_new->file_check=&file_check_psd;
-    return 1;
-  }
-  return 0;
+  reset_file_recovery(file_recovery_new);
+  file_recovery_new->min_filesize=70;
+  file_recovery_new->extension=file_hint_psd.extension;
+  /* File header */
+  file_recovery_new->calculated_file_size=0x1a;
+  file_recovery_new->data_check=&psd_skip_color_mode;
+  file_recovery_new->file_check=&file_check_psd;
+  return 1;
 }
 
 static uint32_t get_be32(const void *buffer, const unsigned int offset)
@@ -126,10 +128,8 @@ static int psd_skip_image_resources(const unsigned char *buffer, const unsigned
 
 static int psd_skip_color_mode(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
 {
-  psd_image_data_size_max=(buffer[buffer_size/2+12]<<8 | buffer[buffer_size/2+13]) *
-    (buffer[buffer_size/2+14]<<24 | buffer[buffer_size/2+15] <<16 | buffer[buffer_size/2+16]<<8 | buffer[buffer_size/2+17]) *
-    (buffer[buffer_size/2+18]<<24 | buffer[buffer_size/2+19] <<16 | buffer[buffer_size/2+20]<<8 | buffer[buffer_size/2+21]) *
-    buffer[buffer_size/2+23] / 8;
+  const struct psd_file_header *psd=(const struct psd_file_header *)&buffer[buffer_size/2];
+  psd_image_data_size_max=(uint64_t)le16(psd->channels) * le32(psd->height) * le32(psd->width) * le16(psd->depth) / 8;
 #ifdef DEBUG_PSD
   log_info("psd_image_data_size_max %lu\n", (long unsigned)psd_image_data_size_max);
 #endif
@@ -157,3 +157,9 @@ static void file_check_psd(file_recovery_t *file_recovery)
   else if(file_recovery->file_size > file_recovery->calculated_file_size + psd_image_data_size_max)
     file_recovery->file_size=file_recovery->calculated_file_size + psd_image_data_size_max;
 }
+
+static void register_header_check_psd(file_stat_t *file_stat)
+{
+  static const unsigned char psd_header[6]={'8', 'B', 'P', 'S', 0x00, 0x01};
+  register_header_check(0, psd_header,sizeof(psd_header), &header_check_psd, file_stat);
+}