How about using subscripted variables (an array) and have $image[1], $image[2], etc?
#include <IE.au3>
#include <Array.au3> ; for testing
$oIE = _IECreate ("[url="http://www.autoitscript.com/"]http://www.autoitscript.com/[/url]")
$oImgs = _IEImgGetCollection ($oIE)
Local $aImgs[@extended + 1] = [@extended], $iImg
For $oImg In $oImgs
$iImg += 1
; $aImgs[$iImg] = $oImg.src ; full path
$aImgs[$iImg] = $oImg.nameprop ; filename only
Next
_ArrayDisplay($aImgs) ; for testing