php - ImageMagik - Saving as a file is ok, but outputing to web page is corrupted

Question

I am using ImageMagik on my Debian server (apt-get install php5.6-imagick).

As expected, this bit of code reads in a picture and saves a copy elsewhere:

$canvas = new Imagick( "/var/www/websites/DisplayScreen/Slideshow Photos/20161016_151555.jpg" );
$canvas->writeImage("/var/www/websites/DisplayScreen/20161016_151555.jpg");

When I change the code to:

$canvas = new Imagick( "/var/www/websites/DisplayScreen/Slideshow Photos/20161016_151555.jpg" );
header( "Content-Type: image/jpg" );
echo $canvas;

and call it from a web page, a file that is a similar size to the original is delevered but is not recognised by the browser (or Paint Shop Pro). The output image seems to have been corrupted.

I have tried header( "Content-Type: image/jpeg" ); and echo $canvas->getImageBlob(); as varients to the above, but get the same result.

All help gratefully received...

question from:https://stackoverflow.com/questions/65646731/imagemagik-saving-as-a-file-is-ok-but-outputing-to-web-page-is-corrupted

Answer 1

It turns out the problem was that I had a blank line in my php source file before the <?php

This, obviously, was being output ahead of the image and therefore corrupting it (but, also obviously, didn't affect writing the image out to disk).