iPhone 15 Pro not sending message pictures.

Settings -> General -> Reset -> Reset All Settings

This solved the problem for me. After this, I am able to send photos in messages to non-iPhone users. Group messages are also working normally again.

This was suggested by Apple Support after I had already tried and failed to fix the issue with my carrier's customer support. You'll have to do a little work to change your settings back to how you like them - including re-setting up alarms.

lorinda0890 wrote:

Why is iPhone 15 Pro not sending pictures? My SMS/MMS is on and I’ve done a network resetting. I have a strong Internet connection and cellar data is on. It’s still not sending pictures to non-iPhone users. Help?

Even though the features are enabled in Settings, they are not properly provisioned in your carrier's system. You will probably need to contact your carrier. But first, try logging into your account with your carrier, either through their website or app. Turn off MMS and group messaging. Restart your phone. Turn the features back on again. If that doesn't work, you'll need to get the carrier to do it on their end.

lorinda0890 wrote:

I have been on the phone with my carrier several times; at first I couldn’t send texts to non-iPhone users and they fixed that. I’ll call them back tomorrow for the 5th time. Thank you!

Something that's worth keeping in mind when calling your carrier. The people you're talking to, even if you select the "technical support" option from the menu, are customer service agents with a little more training and a bunch of procedure documents on how to respond to various issues. I know because I used to train some of them. They're generally very nice people but they get rated on how many calls they take. If you continue having problems, you need to keep escalating the call until you get to actual tech support.

You can try this. Call and ask them to remove MMS messaging. Don't go into why, don't ask too many questions. Thank them when they do and hang up. Restart your phone. Call back and ask them to add MMS to your account.

Don't waste anyone's time, especially yours, by contacting Apple Support. They can't fix this.

I suppose MMS are included/enabled in your SIM plan?

If you tried everything you can it’s worth downloading the Apple Support app and have a chat or call the Apple Support