It is not really appropriate to depict a heavenly creature on a deck of cards is it, let alone riding a bicycle.
At the risk of making too absolute a statement, I don’t think there’s anything wrong with this in any way whatsoever.
We depict heavenly creatures like angels all the time, whether in religious art or in cartoons in the Sunday paper or on a deck of playing cards. Now if the depiction has the angel doing something wrong, or if the depiction is used for something sinful, then that would be a sin. That would be sacreligious. Hence, when South Park has angels saying or doing perverse things, that is sacreligious. When a strip club uses angels on their sign, that is sacreligious.
But there isn’t anything evil about riding a bicycle, nor is there anything evil about playing a card game. So using the angel on there wouldn’t be wrong. Imagine if someone came out with a deck of cards that had a picture of Christ on the back. In fact I am sure you can get thos. I would think most people would consider that great.
I like to ask people what sort of car Jesus would drive. They can be very offended and think that this is such a terrible question. However, it’s actually a very profound question. Jesus became man. He had a home and tools and customers, and He
charged people to do carpentry for them, and all sorts of things like that. If He had become man
today instead of 2,000 years ago, chances are He would have owned a car. If He didn’t, He may have had a bicycle.
Just because something is modern, it doesn’t mean it’s bad. Remember that angels often appeared to people at various time disguised as regular human beings. Should an angel do such a thing today, who’s to say the angel might not ride up to the fellow on a bike?
I hope that helps, but you might get better answers if you explain exactly what you think is improper about having a picture of an angel on a bike, or having a picture of an angel on a deck of cards.