Disabling this WordPress feature which automatically generates various sizes of an uploaded image, is normally as simple as going to WordPress Dashboard > Settings > Media screen and changing all image-size options to
Unless I am missing something, this is not the case with my blog. Any image I upload gets a 92 pixel square thumbnail cousin.
I have searched through all the theme files for any and all occurrences of the number '92', but there's none! So I am guessing it's WordPress core?
This WordPress Codex page says that the default sizes for thumbnail, medium, and large resolution images are 150 px, 300 px, and 640 px (squares) respectively. A 92 px square is clearly not among the defaults.
I read here that WordPress creates "one additional thumb for Dashboard interface needs". I am not sure where. Is this why the 92px thumb is being generated? (I don't think so.)
In case it helps, I am using a WordPress.com theme called "Reddle" on my self-hosted blog. It looks like the theme was developed by Automattic Theme Wranglers.