The best caption for the photo would depend on the context of the image. However, if the image depicts a gathering in nature, the most fitting option might be:
"Vamos al campo los domingos."
If the image shows a religious gathering, then "Vamos a la iglesia los domingos." would be more appropriate.
Without seeing the photo, it's difficult to determine the absolute best option, but those are your main considerations based on the provided sentences.