Ilija Studen:It does not work only for avatars, logos and project icons, but works well for uploaded files? Thumbnails are created properly? If that is the case open config/config.php and make sure that PUBLIC_FOLDER_NAME value is the same as the name of your public folder. This value IS CASESENSITIVE!
Apache Note: Apache has a LimitRequestBody configuration directive. It restricts the size of all POST data regardless of the web scripting language in use. You might need to update this value, too.