What does it mean if a file name ends in .mp4.jpg?

I have several and they are only an inch wide and when enlarged they are
very low quality. They were all taken with a Samsung phone model
SM-A305F in early 2022.

Is it what it sort of sounds like, a still somehow taken while I was
videoing something? Or when I was watching the video?

I don't remember ever doing either of those things, but I have about 100
of them.

How would one take a still picture, one "frame", while filming a video
or watching it? Maybe if I knew how it was done, I'd remember if I did
it.

micky wrote:

> What does it mean if a file name ends in .mp4.jpg?

sounds like an mjpeg

<https://en.wikipedia.org/wiki/MJPEG>

micky <NONONOmisc07@fmguy.com> writes:

> What does it mean if a file name ends in .mp4.jpg?

At a guess, it's a thumbnail picture for a video file. Phones do
thumbnails for photos too. I think it's best to not backup those.

In comp.mobile.android, on Sun, 04 Feb 2024 10:45:08 +0200, Anssi Saari
<anssi.saari@usenet.mail.kapsi.fi> wrote:

>micky <NONONOmisc07@fmguy.com> writes:
>
>> What does it mean if a file name ends in .mp4.jpg?
>
>At a guess, it's a thumbnail picture for a video file. Phones do
>thumbnails for photos too. I think it's best to not backup those.

I may have done it already, but I may find them and delete them. Not
difficult.

I googled, and all I found were instructions of how to convert mp4 to
jpg. Ah, I forgot to put it in double quotes. That helped get hits, 5
of them, but they only talked about how to find them, etc. not what they
were. One guy wanted to play one, so the answer was to rename it
without .jpg. That's not going to work, and it didn't.

And I still don't know where they came from, or how I made them.. Oh,
well.