Leverage server-side HEIC conversion

[swissspidy]

Related:

• Evaluate libheif alternative #483

If WordPress/wordpress-develop#7034 lands and no client-side HEIC conversion is possible, it could be at least done on the server. The thumbnails could still be generated client-side though.

It would make things a bit more complicated:

1. Check whether server supports HEIC
2. Upload HEIC image to the server as a regular attachment
   • Let WP do the conversion server-side, but do not create any thumbnails
3. Get back the converted JPEG on the client
4. Create all thumbnails on the client and sideload them

Might just be a matter of changing order of operations.

Before:

OperationType.TranscodeHeif
OperationType.ResizeCrop // Big image size threshold
OperationType.TranscodeImage // Compress
OperationType.GenerateMetadata
OperationType.GenerateCaptions
OperationType.Upload
OperationType.ThumbnailGeneration

After:

OperationType.Upload
OperationType.GenerateMetadata
OperationType.GenerateCaptions
OperationType.ThumbnailGeneration

[swissspidy]

wp_image_editor_supports( array( 'mime_type' => 'image/heic' ) )