#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?mi)^/pictures/(([a-z0-9]{2,2})([a-z0-9]{2,2})[a-z0-9]{28}\.\w+)"
Local $sString = "/pictures/202cb962ac59075b964b07152d234b70.jpg"
Local $sSubst = "/p/$2/$3/$1"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
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 AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm