I have same image on different pages in website via different paths and different ALT tags.
Same image:
1.Image in blog post - https://example.coml/wp-content/uploads/2018/05/Assessment.png
Alt tag is “Assessment”
2.Image in page - https:/example.com/wp-content/themes/course_new/images/c4.png
Alt tag is “Course”
If you can add quite different alt text to the image on different pages, I would suggest that the image is purely decorative and should have null alt text: alt="".
Remember that while alt text can be useful for search engines, its primary purpose is to replace the image if it is unavailable for any reason. if the image conveys no relevant information, then the alt attribute should be left blank, as above.