Thumbs set to "0" still getting odd sizes

Hello All,
Hope you can help. When i upload an image (either via wp-admin, or third party editor) WP is making thumbnails for my images.

I get three thumbs at strange sizes, 37×37 65×65 & 67×67. I have all image sizes set to 0 in “settings, media” & if i enalbe thumbs in here i also get those created at the correct sizes i specify.

I have tried disabling all my plugins & changing theme but i still get this behaviour. I’ve also checked through the database for anything obvious that might be causing this.

Any ideas? (I’ve also deleted & re-uploaded the WP files).

Thanks,
Ben.