I made a great animation from some photos and tried to send them from the Google photo app, it says it was sent but it doesn't appear on my text messaging app. Not sure yet if the person received it.
If the file is over 300KB, it normally won't send - then you email it (up to about 25MB). If it's still too large, post it on Drive, Dropbox, Mega or some other file site and send the download link via text.