Problem with twitter to see an image

Hello,

Last year, my client did have the problem that when he want to share a post
via twitter, we obtain just the text but no image.
The problem has been solve for many month but now nothing is working.

I did rebuild his site.
I add some code in robot.txt to solve that:

# Disallow everything.
User-agent: *
Disallow: /

# Certain social media sites are whitelisted to allow crawlers to access page markup when links to /images are shared.
User-agent: Twitterbot
Allow: /images

User-agent: facebookexternalhit
Allow: /images

Thank you for support

Andre