[...]

>>    You can delete images through Image-Dired also.  Type @kbd{d}
>>  (@code{image-dired-flag-thumb-original-file}) to flag the image file
>> -for deletion in the Dired buffer.  You can also delete the thumbnail
>> +for deletion in the Dired buffer.  You can also remove the thumbnail
>>  image from the thumbnail buffer with @kbd{C-d}
>>  (@code{image-dired-delete-char}).
>
> Not sure I understand the reason for this.  "Deletion" goes together
> with "delete", so why use "remove" instead?

You're right that it goes with "delete" from the command name but I
thought that "remove" is better because no file is deleted from this
operation.  Only the thumbnail is removed from the thumbnails buffer.
Maybe my english is a bit off here.
-- 
Manuel Giraud