Can I ask what your use case is? Normally you don't want serve users photos as a link because it provides a bad user experience and could lead to URLs that lead to resources, thus reducing your crawl budget. Also, there are ways to track URLs in GA, but not with UTMs.
Ultimately, I wondering if Hubspot would deliver any metrics on the image itself (ie. impressions or clicks) to help me determine reach and engagement .
There isn't an easy way to get those metrics unless you really know what you're doing. If you want to go down the rabbit hole, you're going to want to do some research on "image tracking pixels".
But this isn't something they would have setup by default. Your best bet is to use UTM tags or you can use a service like MailTrack.