I've learned German for 3 months now.

I've looked up some English-German dictionaries for the expression "to consider st/sb as st/sb in German, but the results that I've found were not satisfying. For example, in Collinsdictionary.com, I found an expression "jdn/etw für etw halten" and an example for it "ich habe das Bild für ein Original gehalten". However it means "I thought the picture was an original", rather than "I consider/ or regard".

It would be more convenient if I use German-German dictionaries because they give very detailed explanations. However my level is too low to use them. So I want to ask here that what is its German equivalent of the English expression "to consider something/someone as something/someone" ?

Thank you very much.