diff --git a/block.c b/block.c
index b38940b..3b4d27f 100644
--- a/block.c
+++ b/block.c
@@ -196,7 +196,7 @@ static void bdrv_io_limits_intercept(BlockDriverState *bs,
 }
 
 /* check if the path starts with "<protocol>:" */
-static int path_has_protocol(const char *path)
+int path_has_protocol(const char *path)
 {
     const char *p;
 
@@ -213,6 +213,21 @@ static int path_has_protocol(const char *path)
     return *p == ':';
 }
 
+int bdrv_read_string(BlockDriverState *file, uint64_t offset, size_t n,
+                           char *buf, size_t buflen)
+{
+    int ret;
+    if (n >= buflen) {
+        return -EINVAL;
+    }
+    ret = bdrv_pread(file, offset, buf, n);
+    if (ret < 0) {
+        return ret;
+    }
+    buf[n] = '\0';
+    return 0;
+}
+
 int path_is_absolute(const char *path)
 {
 #ifdef _WIN32
@@ -3884,7 +3899,7 @@ int bdrv_img_create(const char *filename, const char *fmt,
                     char *options, uint64_t img_size, int flags)
 {
     QEMUOptionParameter *param = NULL, *create_options = NULL;
-    QEMUOptionParameter *backing_fmt, *backing_file, *size;
+    QEMUOptionParameter *backing_fmt, *backing_file, *size, *image_file;
     BlockDriverState *bs = NULL;
     BlockDriver *drv, *proto_drv;
     BlockDriver *backing_drv = NULL;
@@ -3965,9 +3980,11 @@ int bdrv_img_create(const char *filename, const char *fmt,
         }
     }
 
-    // The size for the image must always be specified, with one exception:
-    // If we are using a backing file, we can obtain the size from there
+    /* The size for the image must always be specified, with one exception:
+     If we are using a backing file, we can obtain the size from there,
+     but if not, and we are using an image file, we will obtain the size from it.*/
     size = get_option_parameter(param, BLOCK_OPT_SIZE);
+    image_file = get_option_parameter(param, BLOCK_OPT_IMAGE_FILE);
     if (size && size->value.n == -1) {
         if (backing_file && backing_file->value.s) {
             uint64_t size;
@@ -3990,6 +4007,18 @@ int bdrv_img_create(const char *filename, const char *fmt,
 
             snprintf(buf, sizeof(buf), "%" PRId64, size);
             set_option_parameter(param, BLOCK_OPT_SIZE, buf);
+        } else if (image_file && image_file->value.s) {
+            uint64_t size;
+            char buf[32];
+            bs = bdrv_new("");
+            ret = bdrv_file_open(&bs, image_file->value.s, BDRV_O_RDWR);
+            if (ret < 0) {
+                error_report("Could not open '%s'", image_file->value.s);
+                goto out;
+            }
+            size = bdrv_getlength(bs);
+            snprintf(buf, sizeof(buf), "%" PRId64, size);
+            set_option_parameter(param, BLOCK_OPT_SIZE, buf);
         } else {
             error_report("Image creation needs a size parameter");
             ret = -EINVAL;
diff --git a/block.h b/block.h
index c89590d..b523076 100644
--- a/block.h
+++ b/block.h
@@ -152,6 +152,8 @@ int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
                 const void *buf, int count);
 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
     const void *buf, int count);
+int bdrv_read_string(BlockDriverState *file, uint64_t offset, size_t n,
+                           char *buf, size_t buflen);
 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
     int nb_sectors, QEMUIOVector *qiov);
 int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
@@ -306,6 +308,7 @@ char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn);
 
 char *get_human_readable_size(char *buf, int buf_size, int64_t size);
 int path_is_absolute(const char *path);
+int path_has_protocol(const char *path);
 void path_combine(char *dest, int dest_size,
                   const char *base_path,
                   const char *filename);
diff --git a/block/qed.c b/block/qed.c
index 5f3eefa..311c589 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -217,33 +217,6 @@ static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
 }
 
 /**
- * Read a string of known length from the image file
- *
- * @file:       Image file
- * @offset:     File offset to start of string, in bytes
- * @n:          String length in bytes
- * @buf:        Destination buffer
- * @buflen:     Destination buffer length in bytes
- * @ret:        0 on success, -errno on failure
- *
- * The string is NUL-terminated.
- */
-static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
-                           char *buf, size_t buflen)
-{
-    int ret;
-    if (n >= buflen) {
-        return -EINVAL;
-    }
-    ret = bdrv_pread(file, offset, buf, n);
-    if (ret < 0) {
-        return ret;
-    }
-    buf[n] = '\0';
-    return 0;
-}
-
-/**
  * Allocate new clusters
  *
  * @s:          QED state
@@ -437,7 +410,7 @@ static int bdrv_qed_open(BlockDriverState *bs, int flags)
             return -EINVAL;
         }
 
-        ret = qed_read_string(bs->file, s->header.backing_filename_offset,
+        ret = bdrv_read_string(bs->file, s->header.backing_filename_offset,
                               s->header.backing_filename_size, bs->backing_file,
                               sizeof(bs->backing_file));
         if (ret < 0) {
