my iphone 12 suddenly cannot download pictures sent to me by text

Hey Jaymexo,

Are you following the steps here? Send photos and videos in Messages on iPhone - Apple Support

"Work with attachments

In a conversation, you can do any of the following with attachments:

• Save an attachment: Tap  to the right of the message bubble containing the attachment.
• Share, copy, save, or print an attachment: Tap the attachment, then tap  and choose an option.
• Save or copy an attachment: Touch and hold the attachment, then tap Save or Copy.
• Forward a message or attachment: Touch and hold a message or attachment, tap More, select additional items if desired, then tap .
• Delete an attachment: Touch and hold a message or attachment, tap More, select additional items if desired, then tap ."

If you are, how much storage is currently available on your iPhone: How to check the storage on your iPhone and iPad - Apple Support

Does restarting your iPhone help at all? Restart your iPhone - Apple Support

Please let us know the results when you're able.

All the best.