ffmpeg – Trying to add watermark and embedding cover image to my video

Please i’m trying to add watermark and cover photo to my video using ffmpeg. My command successfully added the watermark but refused to include the cover photo. I don’t know what i’m doing wrong.

Here is my command line

ffmpeg -i input.mkv -i watermark.png -filter_complex "[0:v][1:v]overlay=10:10"  -i cover.jpg -map 0:a -c:v libx264 -crf 23 -preset slow -c:a copy -metadata title="Thanks for downloading" -metadata:s:2 mimetype=image/jpeg -disposition:0 attached_pic output.mkv