How to save a PNG image server-side, from a base64 data URI

I'm using Nihilogic's "Canvas2Image" JavaScript tool to convert canvas drawings to PNG images. What I need now is to turn those base64 strings that this tool generates, into actual PNG files on the server, using PHP. In short, what I'm currently doing is to generate a file on the client side using Canvas2Image, then retrieve the base64-encoded data and send it to the server using AJAX: // Generate the image file var image = Canvas2Image.saveAsPNG(canvas, true); image.id = "canvasimage"; canvas.parentNode.replaceChild(image, canvas); var url = 'hidden.php', data = $('#canvasimage').attr('src'); $.ajax({ type: "POST", url: url, dataType: 'text', data: { base64data : data } }); At this point, "hidden.php" receives a data block that looks like ***data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAABE...*** From this point on, I'm pretty much stumped. From what I've read, I believe that I'm supposed to use PHP's *imagecreatefromstring* function, but I'm not sure how to actually create an actual PNG image from the base64-encoded string and store it on my server. Please aid!