How does php directly download images using headers?

How does php directly download images using headers? It is not a compressed package, but a direct download of images in the image format. for example, jpg and png images can be directly downloaded using the header function. Solution: 1. hit header2. Will the output image not? Phpmanual: gd, search for Content-Disposition php. how can I use the header to directly download the image?
It is not a compressed package, but a direct download of images in the image format, for example, jpg or png format. you can use the header function to directly download images.

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1. enter the header.
2. output image

No? Php manual: gd
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Search for Content-Disposition HTTP

PHP code

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Direct download should use the header to jump to the image URL
The path of the sample is http://test.com/pic/test1.jpg

To download
Header ("Location: http://test.com/pic/test1.jpg ")
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   Discussion
   

   
Direct download should use the header to jump to the image URL
   
The path of the sample is http://test.com/pic/test1.jpg
   

   
To download
   
Header ("Location: http://test.com/pic/test1.jpg ")
   

  
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But what the landlord seems to want is download-and I didn't see it clearly. #2 is the truth.