AquaCart Slider PHP Error

Hello. Not sure if this is the correct place as the issue is with Opencart and not WordPress, however it’s the closest category I could find.

I’ve recently had to re-upload my store, and when I did a reinstall of the Aquacart theme and put a slider on the home page, I receive this error:
“Use of undefined constant HTTP_IMAGE – assumed ‘HTTP_IMAGE’ in /home/viainox/public_html/catalog/model/tool/image_custom.php on line 12Notice: Use of undefined constant HTTP_IMAGE – assumed ‘HTTP_IMAGE’ in /home/viainox/public_html/catalog/model/tool/image_custom.php on line 12Notice: Use of undefined constant HTTP_IMAGE – assumed ‘HTTP_IMAGE’ in /home/viainox/public_html/catalog/model/tool/image_custom.php on line 12″

I’m not sure how to resolve the issue. Please advise if you know what might be the problem.
My website is http://viainoxcanada.com

Thank you.