Is there any way of taking a screenshot of a website in PHP, then saving it to a file?
Answer
LAST EDIT: after 7 years I'm still getting upvotes for this answer, but I guess this one is now much more accurate.
Sure you can, but you'll need to render the page with something. If you really want to only use php, I suggest you HTMLTOPS, which renders the page and outputs it in a ps file (ghostscript), then, convert it in a .jpg, .png, .pdf.. can be little slower with complex pages (and don't support all the CSS).
Else, you can use wkhtmltopdf to output a html page in pdf, jpg, whatever.. Accept CSS2.0, use the webkit (safari's wrapper) to render the page.. so should be fine. You have to install it on your server, as well..
UPDATE Now, with new HTML5 and JS feature, is also possible to render the page into a canvas object using JavaScript. Here a nice library to do that: Html2Canvas and here is an implementation by the same author to get a feedback like G+. Once you have rendered the dom into the canvas, you can then send to the server via ajax and save it as a jpg.
EDIT: You can use the imagemagick tool for transforming pdf to png. My version of wkhtmltopdf does not support images. E.g. convert html.pdf -append html.png.
EDIT: This small shell script gives a simple / but working usage example on linux with php5-cli and the tools mentioned above.
EDIT: i noticed now that the wkhtmltopdf team is working on another project: wkhtmltoimage, that gives you the jpg directly