Although I am not Catholic, I know none that worship Mary’s image, revering is not worship.
Wearing a Cross is not worship, it is a simple of remembrance.
I am not sure why you apparently see them as the same.
Idols were objects that are/were worshiped as a god, not reminders.
Idols were not regarded as gods but as sacred objects, little “homes” for the gods. Making an idol was, however, a way of delimiting a god, describing his attributes ,making him physically present by invoking his name. The god of the Jews was noniconic not only in that he could not be properly represented but not even named. Nonetheless, He was localized in the people of Israel and even physically in the tent Tabernacle and in the Temple, where the Ark was his throne.
Wink, wink...