Вы можете использовать, кроме ответ Скотта :
$('<img src="speech_left.jpg" />').prependTo($('.twtr-tweet-text p'));
Отредактировано для добавления простого JavaScript-метода достижения того же:
var elems = document.getElementsByTagName('p'),
leftImageSrc = 'speech_left.jpg',
rightImageSrc = 'speech_right.jpg',
className = 'twtr-tweet-text',
parent, // used in the loop, below
img; // used in the loop, below
for (i=0;i<elems.length;i++){
parent = elems[i].parentNode; // looking at two qualities of the parent,
// so storing it in a variable
if (parent.tagName.toLowerCase() == 'div' && parent.className == className){
// the 'if' tests that the parent is a div, and
// that the parent has a class-name of 'twtr-tweet-text'
// left image:
lImg = document.createElement('img');
lImg.src = leftImageSrc;
// the firstChild of the elems[i] element is the textNode
elems[i].insertBefore(lImg,elems[i].firstChild);
// right image:
rImg = document.createElement('img');
rImg.src = rightImageSrc;
elems[i].appendChild(rImg);
}
}
JS Fiddle demo .