It looks like template.css
is affecting the image to shrink. You can use this CSS on
Template Options -> Custom Code -> Custom CSS
to get rid of the issue.
.sppb-addon.sppb-addon-text-block img {
height: 100%;
}
Or, if you want, then I can check the issue from the backend and suggest a better solution. In this case, I will need the administrator access of the site. Share your administrator access here to check the issue. Use the Hidden Content box to share the credentials. Make sure that you have a full site backup before sharing.