create webpage preview thumbnail using php or firefox extension

What I want to do is to get the webpage 开发者_Python百科preview(or save that as an img) by using the webpage url.

Can anyone point me the way in developing such function in php?

Or if it can be done by using firefox extension, can anyone point me the way in programming it?

I know there are some available sources like "thumbalizr" can help doing this. But they only provide limited usage, or needa pay. And I also know there is also a firefox extension named "screengrab" can do that, but i want to re-develop it so that it can merge with my existing code

If you have your own server you can use wkhtmltopdf library to create the thumbnails. The library also has a jpg version. These libraries use the webkit rendering engine to render the webpage and then create thumbnail in either pdf or jpg.

I have used them in the past and they work great.