image_get_intermediate_size() may return croped image when full image is requested

[dd32]

At present image_get_intermediate_size() is not aware of croped images, infact, Images being croped is not stored in the meta data at all.

This has caused a bug to appear in the twentyten theme which uses a post thumbnail of 940x198px (croped).

If you upload an image 1024x768, and attempt to display it as 640x480, you'll recieve the next largest image which fits, image_get_intermediate_size() will return the 940x198px version. (For example, On the twentyten Attachment page)

The solution i've come accross is to store if the image has been auto-croped in the meta data, and upon retrieval, only return croped images for sizes which speecify croped as OK.

I'm attaching a POC patch, ideally, it should automatically add the list of custom image sizes which are cropped and test against that.

My attachment skips past crops (except for the thumbnail size, which it will always consider), and determines whether an image is a crop by calculations against the full image size (which means it requires no new data storage, and will work with previously uploaded images).

(In [13145]) Skip intermediate sizes of a different aspect ratio than the original image when considering which image to use in image_get_intermediate_size(). fixes #12218

Dupe hunting

#11801
#12210