You can probably achieve what you need using preg_replace_callback and then looping through the image's attributes in the callback function.
So for example, given this test string:
$content= <<<HTML
<img alt="image-alt-2" src="image-path" style="width: 20px; height: 15px; border: 1px solid red;" title="image-title" data-image-src="another_src" />
<p>Some other tags. These shouldn\'t be changed<br />Etc.</p>
<img alt="image-alt-2" src="image-path-2" style="width: 35px; height: 30px;" title="another-image-title" data-image-src="somewhere_else" />
HTML;
We can then match out the images and call our replacement function:
$content= preg_replace_callback('/<img ((?:[-a-z]+="[^"]*"\s*)+)\/>/i', 'replaceImage', $content);
For my example I'm just removing the data-image-src attribute and using it to create the link, everything else is left as it was:
function replaceImage($matches) {
// matches[0] will contain all the image attributes, need to split
// those out so we can loop through them
$submatches= array();
$donelink= false;
$count= preg_match_all('/\s*([-a-z]+)="([^"]*)"/i', $matches[1], $submatches, PREG_SET_ORDER);
$result= '<img ';
for($ndx=0;$ndx<sizeof($submatches);$ndx++) {
if ($submatches[$ndx][1]=='data-image-src') {
// Found the link attribute, prepend the link to the result
$result= "<a href=\"{$submatches[$ndx][2]}\">$result";
$donelink= true; // We've added a link, remember to add the closing </a>
}
// You can handle anything else you want to change on an attribute-by-attribute basis here
else {
// Something else, just pass it through
$result.= $submatches[$ndx][0];
}
}
return "$result/>".($donelink?'</a>':'');
}
Running that on the sample content gives:
<a href="another_src"><img alt="image-alt-2" src="image-path" style="width: 20px; height: 15px; border: 1px solid red;" title="image-title"/></a>
<p>Some other tags. These shouldn\'t be changed<br />Etc.</p>
<a href="somewhere_else"><img alt="image-alt-2" src="image-path-2" style="width: 35px; height: 30px;" title="another-image-title"/></a>
Hope that helps!
