Mastodon profile photos question

Cross-posting
1

I don’t have a mastodon account anywhere and never have.

Where does mastodon get my profile photo from? When a mastodon user replies to my Mb post, a profile of some kind is created on their server, example Hachyderm.io - I assume it’s copied somehow from Mb.

But where did that profile photo come from? It’s not the one I’m currently using. I used to use that photo on Mb. But I changed it early last year.

Thanks

Edit to add a better link as example

https://hachyderm.io/@torb/113782183955166890

2

Is it the one on Gravatar? That’s the only thing I can think of.

3

I double checked and that’s not my current Gravatar photo.

My email is not passed to mastodon server tho, is it?