[wp-trac] [WordPress Trac] #32433: Add registered image sizes in WXR export file

[WordPress Trac]

#32433: Add registered image sizes in WXR export file
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 Reporter:  joehoyle      |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Export        |    Version:
 Severity:  normal        |   Keywords:
  Focuses:                |
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 When a WordPress site is exported, attachments are also exported (though
 only the original image url). If a user then imports that into a new
 WordPress install, images will be generated for all registered image sizes
 on the new blog.

 If however, the exported site was running different image sizes, it will
 potentially have references to those images in post content (e.g. `image-
 322x422.png`); however, `322x422` is not a registered image size on the
 new site. This will produce 404 images in the new post content.

 This was acknowledged (though I don't think addressed) in #16984:

 > A problem that might arise is if there are different image size settings
 on the export and import sites. So an exported post might contain an image
 img-200x200.jpg but the import site hasn't generated the appropriate size.
 For the first patch I'm ignoring this and saying that it's up to the user
 to ensure the settings are consistent. Potential future fixes include
 importing options or generating the extra sizes on the fly

 The user will typically not have control over image sizes either way (as
 they have to be registered in code) - also the recipient of a WXR file
 does not know the image sizes on the exported site.

 It therefore seems logical to include image sizes somewhere in the WXR
 file, so importers (the WordPress importer or otherwise) know what image
 sizes to generate for all existing attachments.

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Ticket URL: <https://core.trac.wordpress.org/ticket/32433>
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