I am very sorry to hear of you not having that option to show images on emails, and can understand the inconvenience and annoyance. The Samsung Email application has a new update that rectifies this. On the older version, you would have to toggle a switch to view all images on every email. The update puts it back to asking for each email as it used to.
To update the Samsung Email application, you can do so in either the Google Play Store or the Galaxy Store, by tapping the magnifying glass icon and searching for "Samsung Email", where you will have the option to update it if it is available.