I know Catholics defend their icons by saying that they are not really graven images, that they merely represent something else. So at what point does it stop being alright and turn into blasphemy. How far does it have to go?
Just so you know, all those other pagan religions techniquely aren’t worshipping statues, they too believe they are worshipping a representation of another power.
I knew that LOL.
As to the question - the issue is one, not of how much, but of direction. If for even one instant one directs one’s heart to any created thing & takes it for God - one has fallen into idolatry.
But no amount of devotion to a saint, of love for his relics, his picture, his image, or anything that puts one in mind of him, is idolatry - provided only that one remembers that the saint is a creature, & is not His Lord & Creator.
God is our God, & only He - in comparison with Him, nothing is good, nothing is holy. He is the Living God, & there neither is nor can be any other.
FWIW, there is no sense of strain or awkwardness involved in adoring God & venerating His Saints, no division of heart or mind or energy between Him & them - because they are not the same kind of being as He; For God is Unique, & altogether Incomparable. They share in His Holiness, in a manner befitting redeemed creatures.
There can be superstition in forgetting that Christ is the Head & holds the primacy - but not idolatry; though even the appearance of idolatry is to be avoided. This is harder to do than may at first appear, as we do not live in a society populated only by Christians: even the most restrained Christian piety will look blasphemous to a Muslim.
BTW - Catholicism is Christian. The phrase “other pagan religions” does therefore not apply

For it is not one of them.