PHP : customize image in share link to facebook

Question

I use a script like the following to share links to facebook :

<a class="facebook" href="https://www.facebook.com/sharer/sharer.php?u=&t=" title="Share on Facebook" target="_parent" onclick="window.open('https://www.facebook.com/sharer/sharer.php?u=' + encodeURIComponent(document.URL) + '&t=' + encodeURIComponent(document.URL), 'sharer', 'toolbar=0,status=0,width=548,height=325'); return false;"></a>

it's just when pop up share to facebook, the picture is too big (according to the original image). How to set the image to be minimized? for example the original size of 700x700 image .. when shared image becomes 200x200. what's the solution ?

Answer 1

According to facebook best practices :

Image Sizes

Use images that are at least 1200 x 630 pixels for the best display on high resolution devices. At the minimum, you should use images that are 600 x 315 pixels to display link page posts with larger images. Images can be up to 8MB in size.

We've also redesigned link page posts so that the aspect ratio for images is the same across desktop and mobile News Feed. Try to keep your images as close to 1.91:1 aspect ratio as possible to display the full image in News Feed without any cropping.

You should also check the open graph protocol , the example of setting page image metadata:

<meta property="og:image" content="http://example.com/ogp.jpg" />
<meta property="og:image:secure_url" content="https://secure.example.com/ogp.jpg" />
<meta property="og:image:type" content="image/jpeg" />
<meta property="og:image:width" content="400" />
<meta property="og:image:height" content="300" />
<meta property="og:image:alt" content="A shiny red apple with a bite taken out" />