$re = '/--palette--;[^;]*;(imagelinks)/';
$str = ' --div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:general,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.general;general,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.headers;headers,bodytext;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:bodytext_formlabel,--div--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:tabs.media,assets,--palette--;LLL:EXT:frontend/Resources/Private/Language/Database.xlf:tt_content.palette.mediaAdjustments;mediaAdjustments,--palette--;LLL:EXT:frontend/Resources/Private/Language/Database.xlf:tt_content.palette.gallerySettings;gallerySettings,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.imagelinks;imagelinks,--div--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:tabs.appearance,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.frames;frames,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.appearanceLinks;appearanceLinks,--div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:language,--palette--;;language,--div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:access,--palette--;;hidden,--palette--;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:palette.access;access,--div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:categories,--div--;LLL:EXT:lang/Resources/Private/Language/locallang_tca.xlf:sys_category.tabs.category,categories,--div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:notes,rowDescription,--div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:extended
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php