We have designed and developed a multilingual chat system, MCHI (Multilingual Chat with Hint Images), which is based on machine translation and equipped with a presentation function of images related to the contents of the messages by utterers so that listeners are able to notice mistranslation. MCHI accepts English, French, Chinese, Japanese, Korean and Vietnamese languages. It uses the Google API to retrieve related images from the image posting site Flickr. As a result of evaluation experiment, we have observed that participants detected the mismatch of a translated message with its related image. According to the answers of participants for a questionnaire, it turned out that the usability of the MCHI system is good enough though the related images are not satisfactory.