publicasteis
-you published
The word publicasteis is the preterite form of publicar in the second person plural.
See the full publicar conjugation

publicar

Esta foto que publicasteis en Facebook...
This picture you posted on Facebook...
Creo que lo publicasteis en respuesta a una petición de un seguidor de chess-poster.
I believe you did publish it in a reply from a request of a chess-poster viewer.
Want to Learn Spanish?
Spanish learning for everyone. For free.
SpanishDict Premium
Have you tried it yet? Here's what's included:
Cheat sheets
No ads
Learn offline on iOS
Fun phrasebooks
Learn Spanish faster
Support SpanishDict