"this," as in yay big "this big," 1950s, perhaps from yea "yes" in its sense of "even, truly, verily." "a sort of demonstrative adverb used with adjectives of size, height, extent, etc., and often accompanied by a hand gesture indicating size" [DAS].
权威例句
1. The fish I caught was yay big.
我钓的鱼有这么大呢。
2. I was then a naughty little child, only yay high.
我那时还是个小顽童, 只有这么高.
3. As you expected, the sharpness remains in exported images . Yay!