<?php
$in = "imgr-3sdfsdf9-266x200.png, pics-asf39-266x800.png, ruh-39-150x200.png, "
. "imgr-3sdfsdf9-1266x20.png, pics-asf39-266x800.PNG, ruh-39-150x200.jpg";
$regex = '/\d+x\d+(\.png)/i';
$repl = '150x150${1}';
echo("Input:\n" . $in . "\n\nOutput:\n" . $out);
?>
PD9waHAKJGluID0gImltZ3ItM3NkZnNkZjktMjY2eDIwMC5wbmcsIHBpY3MtYXNmMzktMjY2eDgwMC5wbmcsIHJ1aC0zOS0xNTB4MjAwLnBuZywgIgogICAgICAuICJpbWdyLTNzZGZzZGY5LTEyNjZ4MjAucG5nLCBwaWNzLWFzZjM5LTI2Nng4MDAuUE5HLCBydWgtMzktMTUweDIwMC5qcGciOwokcmVnZXggPSAnL1xkK3hcZCsoXC5wbmcpL2knOwokcmVwbCA9ICcxNTB4MTUwJHsxfSc7Cgokb3V0ID0gcHJlZ19yZXBsYWNlKCRyZWdleCwgJHJlcGwsICRpbik7CgplY2hvKCJJbnB1dDpcbiIgLiAkaW4gLiAiXG5cbk91dHB1dDpcbiIgLiAkb3V0KTsKPz4K
Input:
imgr-3sdfsdf9-266x200.png, pics-asf39-266x800.png, ruh-39-150x200.png, imgr-3sdfsdf9-1266x20.png, pics-asf39-266x800.PNG, ruh-39-150x200.jpg
Output:
imgr-3sdfsdf9-150x150.png, pics-asf39-150x150.png, ruh-39-150x150.png, imgr-3sdfsdf9-150x150.png, pics-asf39-150x150.PNG, ruh-39-150x200.jpg