$dir = "c:\\project\\data\\";
$files = glob($dir . '*.{jpg,gif,png,jpeg}', GLOB_BRACE);
foreach ($files as $s) {
echo $s . "\n";
}
/*
run:
c:\project\data\abc.jpg
c:\project\data\xyz.jpg
c:\project\data\gdb.gif
c:\project\data\tools.png
c:\project\data\qp.jpeg
...
*/