One solution would be to use the key of your items to remove them -- you can both the keys and the values, when looping using foreach.
For instance :
$arr = array(
'a' => 123,
'b' => 456,
'c' => 789,
);
foreach ($arr as $key => $item) {
if ($item == 456) {
unset($arr[$key]);
}
}
var_dump($arr);
Will give you this array, in the end :
array
'a' => int 123
'c' => int 789
Which means that, in your case, something like this should do the trick :
foreach($images as $key => $image)
{
if($image == 'http://i27.tinypic.com/29yk345.gif' ||
$image == 'http://img3.abload.de/img/10nx2340fhco.gif' ||
$image == 'http://i42.tinypic.com/9pp2456x.gif')
{
unset($images[$key]);
}
}