This was a real issue of mine back in CS-Cart 2.x, and happily, it seems to remain unresolved in CS-Cart 3.x.
Still, we can’t complain when it’s free, right?
The problem
You make a change to a smarty template, eg:
/skins/basic/customer/views/products/components/product_images.tpl
But when you upload the new template, you don’t see any difference.
The solution(s)
The quickest way to refresh appears to be heading in to Administration > Add-ons, then de-activating/re-activating the ‘My Changes’ addon.
This, as far as I can tell, flushes the Smarty template cache.
A page refresh should then show your changes.
If not, try deleting the contents of your:
/var/cache
directory, from your site root. This – in theory – is the smarty template cache dir.
It is hit and miss for me.
Beware of this Gotcha
If you are anything like me, there’s a strong possibility you just spent the last 30 minutes editing the product_images.tpl file in:
\var\skins_repository\basic\customer\views\products\components\
when in fact, you should have been working in:
\skins\basic\customer\views\products\components\
Sigh.
Hope that helps!

{ 2 comments… read them below or add one }
Their documentation is lacking, but this is actually easy to fix (in version 2 – haven’t tried 3 yet)
to clear the cache, simply add ?cc to the end of a page URL
admin.php?cc
Cheers Tim, running *adminfile*?cc didn’t work for me on this occasion, but I should have mentioned it anyway, so thanks for pointing it out.
?cc is still there in 3, I have 3 now running on a few sites, and it’s better but still a good long way off some of the paid e-commerce packages like shopify and big commerce. Still, the price is right!