What values are in the $theme_fwidth and $theme_fheight variables if you var_dump() them prior to that line?
I don’t know wordpress, but looking at the description of the esc_html_e() function, it appears that it’s doing what you asked it to:
"Displays translated text that has been escaped for safe use in HTML output. If there is no translation or the domain isn’t loaded, the escaped original text is shown. "
You pass in “img” as the string to display, so it displays it. What did you want it to display?
This same code is used in a few places on the site, in other placements it works correctly, giving the displayed image Height & Width dimensions, and an Alt = pic name
But for some reason on the Home page this same code is not displaying any values???