First you need to define the alt tags in languages.php.
At the end of english.php add
/* 1.0 */ define("_JR_NEW", "New");
/* 1.0 */ define("_JR_HOT", "Hot");
/* 1.0 */ define("_JR_FEATURED", "Featured");
in jreviews.functions.php
find
function getStandardButtons($row, $settings) {
// New
below it add
global $mosConfig_lang;
then 13-14 lines below, replace with
if ($new || $hot || $featured) {
$this->code = ($new ? '<img alt="'._JR_NEW.'" border="" src="'.JTMPL_JREVIEWS.'/images/'.$mosConfig_lang.'_new.gif"> ' : '');
$this->code .= ($hot ? '<img alt="'._JR_HOT.'" border="0" src="'.JTMPL_JREVIEWS.'/images/'.$mosConfig_lang.'_hot.gif">' : '');
$this->code .= ($featured ? '<img alt="'._JR_FEATURED.'" border="0" src="'.JTMPL_JREVIEWS.'/images/'.$mosConfig_lang.'_featured.gif">' : '');
I changed my extensions to transparent gif because of IE problem with png not being transparent
Rename the 3 images hot.png new.png and featured.png by adding the prefix in front of them, e.g. english_hot.png
do the same for every language.
Now, you can display proper image depending of your language.