As a spanish, I don't understand why they did this pic because even if it was a 'nice' pose it doesn't look good. I suppose it was some kind of "we're all going to China" or somerthing stupid that any of them wanted to do and the other followed.
But it's no-where an offensive thing. I mean, doing that pose isn't "a way of insulting chinese people" in Spain. If we want to insult a chinese, we just call them something (not me, I'm generalizing) but we don't do that with the eyes. It's the opposite, I've done that pose a hundred times and it's nothing to do with offending but just to imitate a chinese. As if I want to imitate an african and I try my lips to be bigger and talk different. Somthing like that. Or when people say "ole! paella" when they want to imitate spanish people.