Further to this original suggestion , and Sara Arjona's encouraging response, I'd like to propose that the course images shown in the Card view of the Course overview block on the My courses page also be fitted with telling tool-tips - just like the truncated titles are likely to shortly be - as per the current developments in MDL-77364 :

Further, for consistency, if such tool-tips are added in the Card view, I would propose that the other views (Summary and List) followed suit - the course images shown there might also feature such explanatory tool-tips. Such seems to be the practice od media sites, where article titles and photos accompanying them on the front page both tend to employ links to the article with explanatory on-hover tool-tips.