[FIXED] How to store data in an image with php?

Issue

I have tried to use the imagick library to create two functions like this:

function storeCoordinatesImage($img_path, $coordinates){
    $im = new imagick($img_path);
    $im->setImageProperty("coords", $coordinates);
    $im->writeImage($img_path);
}

function getCoordinatesImage($img_path){
    $im = new imagick($img_path);
    return $im->getImageProperty("coords");
}

If I run:

if(!storeCoordinatesImage("I.jpg", "hi")) echo "fal";
echo getCoordinatesImage("I.jpg");

Nothing is returned.

But if I run:

$im = new imagick($img_path);
$im->setImageProperty("coords", "hello");
echo $im->getImageProperty("coords");

it returns "hello".

So it must be some issue with writing to the image? Although none of these functions are returning false. (i.e they are all working)

Solution

As Ben mentioned this is not possible. Instead you can add a "comment":

function storeCommentImage($img_path, $coordinates){
    $im = new imagick($img_path);
    $im->commentImage($coordinates);
    return $im->writeImage($img_path);
}

function getCommentImage($img_path){
    $im = new imagick($img_path);
    return $im->getImageProperty("comment");
}

Answered By - maxisme

Answer Checked By - Marilyn (PHPFixing Volunteer)