Questions about php image creation

Php image creation question // length and height $ _ width = 75; $ _ height = 25; // create an image $ _ img = imagecreatetruecolor ($ _ width, $ _ height); // white $ _ white = imagecolorallocate ($ _ img, 255,255,255); // fill in I php to create an image
// Length and height
$ _ Width = 75;
$ _ Height = 25;

// Create an image
$ _ Img = imagecreatetruecolor ($ _ width, $ _ height );

// White
$ _ White = imagecolorallocate ($ _ img, 255,255,255 );

// Fill
Imagefill ($ _ img, 0, 0, $ _ white );




// Output image
Header ('content-Type: image/png ');
Imagepng ($ _ img );

// Destroy
Imagedestroy ($ _ img );
In Firefox
The above code turns the background of the entire page Gray, and the image is in the middle. However, the tutorial I read is normal, and other browsers are also normal.

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That's the problem with the browser.
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You can use php to save the image as a file and use Firefox to open it. You will know if it is a browser issue.
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I remember, it seems that Firefox displays images in this way. put them in the middle. your images are generated correctly.