I have an Android phone but among the users of my family plan are both those and iPhones. Everyone has a gmail email account and everyone's image appears with calls. As do images from many other people I know who call me.

If you use Google's Contact and Calendar services to sync with your iPhone, you can take advantage of the feature "Set Profile photo" or "Set Contact photo". By choosing a photo from your PC or phone for one's account setting, I believe that causes people you call to see that image when you call them.

The image also appears for text messages. Also with emails, whether or not the phone originates the email message. I think what happens is the Google system associates the other person's image with their entry in your contact file and so shows it. But maybe not, it may work the other way around.

Go into contacts, edit, add photo.

Sorry - I misinterpreted the question. My answer sets a chosen image for someone who calls you. Elmer’s is how to have the world see you.

ETA - Settings, click on your Apple ID, there’ll be an edit button by your initials where you can add an image.

FOAS, ok I made the image but when I called DH it did not appear on his phone when it rang. How to make it work that way?

Sorry my kids messed with this once and I thought it’s what they did. But you’re right it didn’t work for me either. Elmer’s probably more on track.

One thing I’ve noticed is that when it’s coming from someone else, you have to accept the image, and that adds it to their contact photo on your phone. Without accepting it, it still hangs out there as a suggestion but doesn’t add.

"I think the receiver has to set the photo."

I'm not sure that's the case.
Doing it the way I outlined I most certainly have images in my contact file that pop up what I receive a call or message from people whose image I did not put into my contract record. But they are people I had a previous contact entry for. That's why I said I wasn't sure which way the originating photo came from, the sender or the receiver, because I also have some images that I put into a contact file that also appear when those people call or message me. Maybe with Google it works both ways?

I thought you were talking about making an emoji of yourself. If so, here is one way:

more info:

https://support.apple.com/en-us/HT208986

Yes, that's what I wanted. I made it, but not sure how to make it pop up on people's phone when I call them.

"not sure how to make it pop up on people's phone when I call them"

Socks, please see my earlier comments. Try the steps I outlined and see what happens. It worked for me, let us know if it works for you too.