What do these small hiragana (ぁぃぅぇぉ) mean?
I know how to use these kana (やゆよ) to make things like きゃ and りゅ, but I've never seen those small kana used in context. What are they used for?Sorry, I worded that kind of strangely. I meant that I know what the small "やゆ and よ" characters are for, but I don't know what these are for "ぁぃぅぇ and ぉ", since they're small.

Question

What do these small hiragana (ぁぃぅぇぉ) mean?
I know how to use these kana (やゆよ) to make things like きゃ and りゅ, but I've never seen those small kana used in context. What are they used for?Sorry, I worded that kind of strangely. I meant that I know what the small "やゆ and よ" characters are for, but I don't know what these are for "ぁぃぅぇ and ぉ", since they're small.

Answer

Recently we can see small ぁ・ぃ・ぅ・ぇ・ぉ（hiragana）instead of usual(big) あ・い・う・え・お.
I found the next examples on the Internet.
株式会社くればぁ　※clever→クレバー→くればあ→くればぁ（I guess）
ほぁんほぁん本店  ※ホアンホアン(a name of giant panda)→ほあんほあん→ほぁんほぁん（I guess）
※I think that they wanted to make their company's / restaurant's name outstanding.

あぁYes / Oh 「あぁ、いいよ、んなこと。 あ、それでさ、葵ちゃん」 / あぁ神様、お願いします
いぃ(groan) （にゅっ！ んくっ！ うくっ！ いぃっ！ むぅっ！ いぃっいぃっ！） （←ムチを振っている） どぉ？ 痛い ？ 痛い？
えぇYes 「えぇ、いいですよぉ。どうぞどうぞ」っと言って自宅に通してくださったのは近江かおりさん。
おぉYes / Wow  おぉ～、いいともよ。好きなだけ持って行きな。/ おぉ。。まさにこれはハトサブレ！？
うぅ(groan)　「うぅっ、PR企画が浮かばないっっ！」
ちかれたぁ〜　※つかれたI'm tired→ちかれたあ〜→ ちかれたぁ〜
やっぱりいぃよなぁ～！After all it is good !
体くっせぇしきたねぇなぁぁ(≧ω≦)  ※きたないなあ→きたねえなあ→きたねぇなぁ
※I think that they think the part of long vowel is not a formal sound. Actually there are no long vowel in old Japanese. They were born by two reasons. One reason is that kanji came to Japan. Another reason is that the consonant dropped out as a result of the euphonic change.

※
small ぁ　http://ja.wikipedia.org/wiki/%E3%81%81（Japanese）
　　　　　https://en.wiktionary.org/wiki/%E3%81%81（English）
small ぃ　http://ja.wikipedia.org/wiki/%E3%81%83（Japanese）
          https://en.wiktionary.org/wiki/%E3%81%83#Japanese（English）
small ぅ　http://ja.wikipedia.org/wiki/%E3%81%85（Japanese）
          https://en.wiktionary.org/wiki/%E3%81%85#Japanese（English）
small ぇ　http://ja.wikipedia.org/wiki/%E3%81%87（Japanese）
          https://en.wiktionary.org/wiki/%E3%81%87#Japanese（English）
small ぉ　http://ja.wikipedia.org/wiki/%E3%81%89（Japanese）　
　　　　　https://en.wiktionary.org/wiki/%E3%81%89#Japanese（English）

Answer

Good question. They are used for the words from other languages and the names and titles which came from other countries when we write them in katakana. (They don't have meaning.) For example: 
ファン fan  
フィート feet
トゥモロー tomorrow
フェスティバル festival 
ウォーター water

I hope this was helpful.

Answer

well, we use those small characters when it's needed. because in hiragana nor katakana, they dont have the words like " Ryo, Kyo, Myo .... ". there's only characters with vowel a,i,u,e,o. that's why we use those small character when the words is like じゃない (Janai) きょ (Kyo)  りょかい (ryokai) etc. if you're still confuse with the explanation. tell me ^^

Answer

いべs知恵伊勢絵mきんだ

Answer

JapaneseSpecialist-san added more explanations that I didn't. Please take his answer! Anyway, good luck to you! Best.