file.html:
..
<img src="script.php"/>
..
script.php:
$name = 'http://upload.wikimedia.org/wikipedia/ru/thumb/c/c5/JPEG_example_down.jpg/350px-JPEG_example_down.jpg'';
$f = fopen($name,"rb");
header('Content-Type: image/jpeg');
while(!feof($f))
echo fread(f,8192);