How can I get a link to a picture loaded in the canvas with PHP?

There are some pictures in 1.canvas, I want to use PHP to get these pictures in the canvas link, the picture downloaded to the computer.
2. If it is a picture in a webpage, can get to the picture path, then use similar file_get_contents function, can download the picture to the machine.
3. The problem now is that I can't get the path to these pictures in the canvas.
4. Ask if PHP is available to get the path to the pictures loaded in the canvas.

Reply content:

There are some pictures in 1.canvas, I want to use PHP to get these pictures in the canvas link, the picture downloaded to the computer.
2. If it is a picture in a webpage, can get to the picture path, then use similar file_get_contents function, can download the picture to the machine.
3. The problem now is that I can't get the path to these pictures in the canvas.
4. Ask if PHP is available to get the path to the pictures loaded in the canvas.

PHP gets two general methods:
First, through the Rules page crawl
Second, the previous page through the AJAX submission to PHP processing

You can save the path of these images with a variable while the canvas is getting the picture, and when the canvas todataurl, you can submit the variable to the background.

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