Not sending picture messages

Cellular Data or Wi-Fi Issues: This is the most likely reason. Your iPhone needs a good internet connection to send iMessages.

SMS messages typically don't require an internet connection, so cellular data wouldn't be the direct cause. They rely on a cellular network connection for sending and receiving.

Here are some revised possibilities why your SMS might not be sending:

• Cellular Network Issues: While not requiring data, SMS still uses the cellular network. Check your signal strength and ensure you're in an area with good cellular reception.
• Carrier Problem: There might be a temporary issue with your carrier's network that's preventing SMS messages from going through. You can try contacting your carrier to see if they're aware of any outages.
• Phone Number Issues: Double-check the recipient's phone number for any typos or incorrect formatting.
• iPhone Settings: There aren't any settings on the iPhone directly for SMS, but in rare cases, a setting related to messaging could be malfunctioning. Try restarting your iPhone as a general troubleshooting step.

If none of these solutions work, it's best to contact your carrier's customer support for further assistance. They can investigate the issue further and see if there's a problem specific to your account.