Get images from a URL and retrieve them all to select the one which is the biggest

Question

I want to open a URL and RegEx all the image's URLs from the page. Then I want to cURL all of them and check what size they have. In the end I want to get the biggest one. How do I do this?

Regular expressions are a horrible way to scrape HTML. – Matthew Mar 20 '10 at 17:35 — Matthew, Mar 20 '10 at 17:35
Is biggest one the dimentions or the filesize? – Mar 20 '10 at 17:42 — , Mar 20 '10 at 17:42

score 2 · Answer 1 · answered Mar 20 '10 at 17:40

2

You could start with getting the URL using curl, saving it in a variable.
Then you could apply a regex like this one: <img.*?src=['"](.*?)['"]>

Check if the source starts with http or is a relative link, if its a relative link you can prepend the url of the page.

Finally get the size of the images using getimagesize() http://php.net/manual/en/function.getimagesize.php

answered Mar 20 '10 at 17:40

gX.

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What about img tags with a newline somewhere in it? – Mar 20 '10 at 18:05
What about img tags which are closed? – Mar 20 '10 at 18:05
What about images loaded using AJAX? – Mar 20 '10 at 18:07
What about images loaded using a plug-in? – Mar 20 '10 at 18:08
hehe trust me i get the point, I went through the complete CodingHorrors article :) – gX. Mar 20 '10 at 18:10

score 1 · Answer 2 · answered Mar 22 '10 at 02:59

Use the php DOM to find the images.

I have not tested this code at all, but it should get you headed in the right direction.

$urls = array();
$dom = DOMDocument::loadHTML(YOUR_HTML);
$imgList = $dom->getElementsByTagName('img');
$imgCount = $imgList->length;
for ($i = 0; $i < $imgCount; $i++) {
    $imgElement = $imgList->item($i);
    if ($imgElement->hasAttribute('src')) {
        $urls[] = $imgElement->getAttribute('src');
    }
}

If you want to get linked images, you can change 'img'/'src' to 'a'/'href'. But you will need to find a way to filter the list to get only images.

You did not say what your criteria is for image size, so I can't help you there. Do you want maximum file size or resolution?

score 0 · Answer 3 · answered Mar 22 '10 at 03:10

It might be already obvious by now, use a DOM parser, not regex. Just get all elements by tag name <img> and then get for each the URL from its src attribute. To determine the image's size without downloading the entire image, you'd probably like to fire a HTTP HEAD request instead and then determine the Content-Length header in the obtained response. The http_head() may be useful in this.

Get images from a URL and retrieve them all to select the one which is the biggest

3 Answers3