[wp-trac] [WordPress Trac] #41801: add wp_get_image_extensions() and wp_image_extensions filter

[WordPress Trac]

#41801: add wp_get_image_extensions() and wp_image_extensions filter
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 Reporter:  pbiron                  |       Owner:  pbiron
     Type:  enhancement             |      Status:  assigned
 Priority:  normal                  |   Milestone:  Future Release
Component:  Media                   |     Version:  4.9
 Severity:  normal                  |  Resolution:
 Keywords:  has-patch dev-feedback  |     Focuses:
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Comment (by gmariani405):

 Hello,

 I'd like to add to this ticket a suggestion on improving the functionality
 here. I have a use-case where I'm trying to display a set of posts using a
 custom post type in Elementor. When Elementor goes to render and the
 option to display the featured image is selected, it calls
 wp_attachment_is_image() on the individual post which in turn calls
 wp_attachment_is('image', $post).

 That is all fine and dandy, except that if the attachment is a PDF this
 will fail. Which shouldn't happen (if ImageMagick is installed), because
 as of 4.7, WordPress creates a thumbnail for PDFs. So technically it does
 have a valid image that could be displayed.

 In order to get this to work, we would need something like what @pbiron
 has added, a filter to add the 'pdf' extension (or include it in core).
 But we also need it to allow the post_mime_type to allow 'application/pdf'
 (or the like). Because right now it fails at this part in WordPress 5.4.2:

 {{{#!php
 <?php
 if ('import' !== $post->post_mime_type) {
     return $type === $ext;
 }
 }}}

 testing with something like this and adding 'pdf' to the list of allowed
 extensions lets it to work as expected:

 {{{#!php
 <?php
 if ('import' !== $post->post_mime_type && 'application/pdf' !==
 $post->post_mime_type) {
     return $type === $ext;
 }
 }}}

 Now, not to say that should be the solution, you guys know how WordPress
 functions (and should function) better than I. But if something like this
 could be customizable or added to core in some fashion that would be
 great.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/41801#comment:26>
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