myDEBUG error throw every time a product info page is viewed

[shags38]

v1.5.7b, responsive classic template, PHP v7.4.13

the following error is being thrown every time a product info page is viewed and I'm not sure how to resolve the problem. The best I can ascertain is that it has something to do with zen_colorbox script however I could be way out.

Would appreciate some assistance please.

cheers, Mike

not sure if this has any relevence https://www.zen-cart.com/showthread....t-thread/page2

[26-Jan-2021 12:10:12 Australia/Sydney] Request URI: /half-hoop-hoop-clip-on-earrings/large-silver-hoop-clip-on-earrings-twisted-knot-design?cPath=1&, IP address: 115.166.19.58
#1 require(/includes/templates/responsive_classic_1/templates/tpl_modules_main_product_image.php) called at [/includes/templates/responsive_classic_1/templates/tpl_product_info_display.php:58]
#2 require(/includes/templates/responsive_classic_1/templates/tpl_product_info_display.php) called at [/includes/modules/pages/product_info/main_template_vars.php:153]
#3 require(/includes/modules/pages/product_info/main_template_vars.php) called at [/includes/templates/responsive_classic_1/common/tpl_main_page.php:178]
#4 require(/includes/templates/responsive_classic_1/common/tpl_main_page.php) called at [/index.php:94]
--> PHP Warning: Use of undefined constant LARGE_IMAGE_WIDTH - assumed 'LARGE_IMAGE_WIDTH' (this will throw an Error in a future version of PHP) in /includes/templates/responsive_classic_1/templates/tpl_modules_main_product_image.php on line 24.

[26-Jan-2021 12:10:12 Australia/Sydney] Request URI: /half-hoop-hoop-clip-on-earrings/large-silver-hoop-clip-on-earrings-twisted-knot-design?cPath=1&, IP address: 115.166.19.58
#1 require(/includes/templates/responsive_classic_1/templates/tpl_modules_main_product_image.php) called at [/includes/templates/responsive_classic_1/templates/tpl_product_info_display.php:58]
#2 require(/includes/templates/responsive_classic_1/templates/tpl_product_info_display.php) called at [/includes/modules/pages/product_info/main_template_vars.php:153]
#3 require(/includes/modules/pages/product_info/main_template_vars.php) called at [/includes/templates/responsive_classic_1/common/tpl_main_page.php:178]
#4 require(/includes/templates/responsive_classic_1/common/tpl_main_page.php) called at [/index.php:94]
--> PHP Warning: Use of undefined constant LARGE_IMAGE_HEIGHT - assumed 'LARGE_IMAGE_HEIGHT' (this will throw an Error in a future version of PHP) in /includes/templates/responsive_classic_1/templates/tpl_modules_main_product_image.php on line 24.