diff --git a/ChangeLog b/ChangeLog
index b7fad021..925eb6ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -17,6 +17,7 @@
 - fix sharpen with sigma 0.5 [2h4dl]
 - sharpen restores input colourspace
 - verify bands/format for coded images
+- improve data_length handling for jpeg metadata
 
 24/5/19 started 8.8.1
 - improve realpath() use on older libc
diff --git a/libvips/foreign/jpeg2vips.c b/libvips/foreign/jpeg2vips.c
index 1060bc9e..d4af258f 100644
--- a/libvips/foreign/jpeg2vips.c
+++ b/libvips/foreign/jpeg2vips.c
@@ -307,7 +307,7 @@ find_chroma_subsample( struct jpeg_decompress_struct *cinfo )
 }
 
 static int
-attach_blob( VipsImage *im, const char *field, void *data, int data_length )
+attach_blob( VipsImage *im, const char *field, void *data, size_t data_length )
 {
 	/* Only use the first one.
 	 */
@@ -333,7 +333,7 @@ attach_blob( VipsImage *im, const char *field, void *data, int data_length )
  * the real XMP.
  */
 static int
-attach_xmp_blob( VipsImage *im, void *data, int data_length )
+attach_xmp_blob( VipsImage *im, void *data, size_t data_length )
 {
 	char *p = (char *) data;
 	int i;
@@ -496,7 +496,7 @@ read_jpeg_header( ReadJpeg *jpeg, VipsImage *out )
 	for( p = cinfo->marker_list; p; p = p->next ) {
 #ifdef DEBUG
 {
-		printf( "read_jpeg_header: seen %d bytes of APP%d\n",
+		printf( "read_jpeg_header: seen %u bytes of APP%d\n",
 			p->data_length,
 			p->marker - JPEG_APP0 );
 
@@ -593,7 +593,7 @@ read_jpeg_header( ReadJpeg *jpeg, VipsImage *out )
 		default:
 #ifdef DEBUG
 			printf( "read_jpeg_header: "
-				"ignoring %d byte APP%d block\n", 
+				"ignoring %u byte APP%d block\n", 
 				p->data_length, p->marker - JPEG_APP0 );
 #endif /*DEBUG*/
 			break;