diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
index 175b854b6a..5dc7e1230f 100644
--- a/libavformat/img2enc.c
+++ b/libavformat/img2enc.c
@@ -42,7 +42,6 @@ static int write_header(AVFormatContext *s)
     VideoMuxData *img = s->priv_data;
     const char *str;
 
-    img->img_number = 1;
     av_strlcpy(img->path, s->filename, sizeof(img->path));
 
     /* find format */
@@ -137,6 +136,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
 #define ENC AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption muxoptions[] = {
     { "updatefirst",  "", OFFSET(updatefirst),  AV_OPT_TYPE_INT,    {.dbl = 0},    0, 1, ENC },
+    { "start_number", "first number in the sequence", OFFSET(img_number), AV_OPT_TYPE_INT, {.dbl = 1}, 1, INT_MAX, ENC },
     { NULL },
 };