How do you say “Me too!” in Korean?

= 저도요! [jeo-do-yo!] / 나도! [na-do!]

How do you say “Is that your real picture?”in Korean?

= 그거 진짜 OO 씨 사진이에요? [geu-geo jin-jja OO ssi sa-ji-ni-e-yo?]

How do you say “Do you have a bigger or smaller size of this?” in Korean?

= 더 큰/작은 거 있어요? [deo keun/ja-geun geo i-sseo-yo?]

or 더 큰/작은 사이즈 있어요? [deo keun/ja-geun ssa-i-jeu i-sseo-yo?]

How do you say “Please be quiet.” in Korean?

= 조용히 하세요. [jo-yong-hi ha-se-yo.]

or 조용히 해 주세요. [jo-yong-hi hae ju-se-yo.]

How do you say “I need to think about it.” in Korean?

= 생각 좀 해 볼게요. [saeng-gak jom hae bol-ge-yo.]

or 생각 좀 해 봐야 될 것 같아요. [saeng-gak jom hae bwa-ya doel geot ga-ta-yo.]