Good evening Cheryl and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
I would love to help you with this topic.
If I understand correctly, you are mostly interested in making sure that the image takes the full width of the image container. Can you confirm ?
The simplest approach to this is to make sure you are using images that all have the same ratio (which typically requires a bit of editing before publishing).
Another solution would be to give the following approach a shot: https://theeventscalendar.com/knowledgebase/change-photo-view-to-equal-height-grid/
Let me know if that helps.
Have a great day!
Geoff B.