Q: How can I send pictures in photos by email? - it says they are too big

Most e-mail provider limits to 10/20 MB, so you might need to break it down to send.

Try sending then with Mail Drop using your icloud email account.

iCloud: Add an attachment to an email

Mail Drop limits - Apple Support

http://www.macworld.com/article/2843396/how-to-make-the-best-use-of-mail-drop.ht ml

talk to your mail provider or send them separate maybe at a lower resolution