Image post format insertion results in a broken image for unlinked images

[designsimply]

Steps to reproduce:

1. Go to Appearance > Themes and activate the Twenty Twelve theme
2. Go to Posts > Add New
3. Click the "Image" post format at the top
4. Click "Select / Upload Image"
5. Upload a new image and set Link To = None
6. Click "Select Image"
7. Note that the "_format_image" textarea contains a link even though I selected Link To = None (looks like a separate bug), remove the anchor tag so just the img tag is left (that's the expected behavior for what I selected). See the highlighted part of the first screenshot below for an example.
8. Click "Publish"
9. View the post

• Expected: to see an image post format appear normally with the image showing
• Actual: no image appears and I see the following mangled HTML:

<div class="post-format-content">
<p><img src="&lt;img src=" http:="" threedotonefour.com="" wp-content="" uploads="" 2013="" 01="" img_3754.jpg"="" width="300" height="225" alt="IMG_3754" class="wp-image-223 alignright size-medium">” alt=”" /&gt;</p></div>

Tested with

• WP Trunk r24075
• Twenty Twelve theme
• Chrome 26

Notes

• I see the same problem regardless of whether I use the "Select / Upload Image" link to add the image.
• As long as the "Image HTML or URL" field contains an unlinked image with code similar to the example above, the image appears broken on the front end.
• The same problem happens even if you simplify the HTML in the "Image HTML or URL" field to something like <img src="http://threedotonefour.com/wp-content/uploads/2013/01/DCP00684.jpg" />

This is *very* similar to #24147 but the output HTML is different.

[wonderboymusic]

This is the result of a bad merge of patches - on it!

[markjaquith]

In 24078:

Fix mangled image output in compat function.

props wonderboymusic. see #24175.

[aaroncampbell]

Several things have changed so I can't follow the steps exactly, but from what I can tell this is fixed:

• In [24226] the "Attachment Display Settings" section of the media modal was hidden, so you can't set a "Link To" there anymore
• In [24289] we made sure that no link was filled in anywhere when you select an image or when you upload one using the new DND functionality
• In [24078] wonderboymusic fixed the mangled output.

I think this is ready to be closed as fixed.