When you say &#"Esto es la repanocha&#" &#(&#"This is...&#"&#) it means this is amazing. You use it when you admire something, when you think it&#'s great. You can say &#"estas fotos son la repanocha&#" &#(&#"these photos are &#"la repanocha&#"&#"&#). It is not widely used in Spanish, and sometimes people might find the expression a bit funny and somewhat dated.
