Editor: Correct image rotation by always passing image through Photon

[aduth]

Partial fix for #313, many caveats apply (see section below)

This pull request seeks to correctly display images with rotation EXIF metadata in the post editor for Jetpack sites. The changes here revise the restrict-size TinyMCE sub-plugin to pass all images through Photon. The reason this helps fix the rotation is described in more detail in #313:

The cause appears to be that WordPress strips EXIF rotation data when generating intermediate thumbnail sizes for an image. Since we display the large thumbnail in the editor, it will display in the editor without the proper rotation. On the site, however, Jetpack/Photon instead use the original image passed through Photon and scaled to the desired size. Because it scales the original image, the rotation metadata is correctly preserved.

Before	After

These changes do not fix rotation issues with featured image. Featured image is more complicated because we respect custom theme size and crop. Because the thumbnail resizing is the cause for the rotation issues, we either must choose (a) to ignore custom thumbnail and pass original image through Photon or (b) to respect custom thumbnail at cost of rotation issues.

Testing instructions:

Using example rotated images, try inserting images into post content. Observe that rotation is restored after image finishes uploading.

1. Navigate to post editor
2. Select a Jetpack site
3. Drag n' drop or otherwise insert image
4. After image finishes uploading, note that rotation is corrected

Caveats:

• Rotation is only fixed after the image finishes uploading
• As can be seen by running through example images, this does not appear to help resolve flipped images, only rotated
• Keep in mind that your browser will probably fix rotation itself when viewing an image in a standalone tab

[matticbot]

Test live: https://calypso.live/?branch=update/editor-photon-always

[aduth]

cc @iamtakashi

[beaulebens]

Seems to test as suggested by your description for me. So I see it initially "incorrectly rotated", but then once the upload completes, then it rotates properly.

[lancewillett]

@aduth Do you want more testing? Is it ready to merge?

[aduth]

@lancewillett I think this could be shippable, though puts us in a weird partly-fixed state with all its caveats. Better overall than what exists currently?

[lancewillett]

@aduth Yes, in my opinion worth the step in the right direction.

[aduth]

I'll plan to merge this Monday morning.