@Haque Thanks for your reply.
Re your points:
The square thumbnail in Dataverse table views is normal and does not mean the original image is lost.
Good to know--this is helpful, thank you. Is it safe to presume then that the full image is actually available for calling on elsewhere in the app for full rendering?
Use Power Apps image controls to display the full image from the image column.
I've tried this and I seem to have no luck If I place an image control to test calling up the image from the Image column in the Dataverse table, it still displays as a square thumbnail. Further along in the app, I call up the image to display to the user. See my screen capture embedded below... one of my screens from my app 'in progress':

For original image storage without thumbnailing, consider file columns in Dataverse.
Originally I had used the file column, however, I don't get the photo showing--rather, it appears as an attachment.
The image column in Dataverse stores images and automatically generates thumbnails for display in views and forms.
Noted - wondering then if the full image can ever be displayed in a form? Wondering if there is a workaround for this?
Thanks again for your assistance, Haque.