Those two are the same meaning but the way to use are different. you can say "小さなバッグ" or "小さいバッグ". But about "小さな", You can just connect it to another word as it is, but it's impossible to chenge it to the past tense or the negative sentence. eg: 小さなだったバッグ or 小さなじゃないバッグ. But you can change a word of "小さい" to the past or the negative. eg: 小さくなかったバッグ or 小さくないバッグ. That's the big difference of them.

「小さな」is more subjective and gets little bit emotion than「小さい」.「小さい」is only stated the facts. ex.「小さな手」---small (and cute) hand, 「小さい手」---(just)small hand If you want to put this adjective to the word "思いやりcompassion", the "小さな" is more appropriate than "小さい" , I think.