<?php
$str = "
Line 1: This is a string
Line 2: [img] image_path [/img] Should not be [img] image_path2 [/img] included.
Line 3: End of test [img] image_path3 [/img] string.";
PD9waHAKJHN0ciA9ICIgCkxpbmUgMTogVGhpcyBpcyBhIHN0cmluZyAKTGluZSAyOiBbaW1nXSBpbWFnZV9wYXRoIFsvaW1nXSBTaG91bGQgbm90IGJlIFtpbWddIGltYWdlX3BhdGgyIFsvaW1nXSBpbmNsdWRlZC4gCkxpbmUgMzogRW5kIG9mIHRlc3QgW2ltZ10gaW1hZ2VfcGF0aDMgWy9pbWddIHN0cmluZy4iOyAKCnByZWdfbWF0Y2hfYWxsKCJ+XFtpbWddKC4rPylcWy9pbWddfmkiLCAkc3RyLCAkbSk7IAoKdmFyX2R1bXAoJG1bMV0pOw==