Is this possible?

[sodoy]

dynimages["<? echo "$imageid"; ?>"]=["<? echo "../images/$imgfilename"; ?>"]

[HardCoded]

Yes, but isn't it:
dynimages[<? echo "$imageid"; ?>]="<? echo "../images/$imgfilename"; ?>"

and maybe this is clearer:
dynimages[<?=$imageid ?>] = "../images/<?=$imgfilename ?>"