Reveal clue or not?

The murder is committed in a place were several people have studio spaces (they are all artists). All the artists have secrets/pasts that the MC learns about over time. Eventually she is in a place and sees a piece of art that is the turning point in her figuring out who the murderer is.

What sounds better: what the MC sees is not revealed to the reader. Rather the next scene has the MC in place at a trap she created to catch the murderer and the reader does not know who it is until the murderer walks into the trap. Or the MC immediately says what she sees and takes the reader along as she sets up the trap?

I would consider it cheating to withhold information from the reader that the MC knows. What works better is having the clue be subtle enough that the reader does not recognize it as such until later on.

I agree. Mention the piece of art the MC is drawn to. Describe it, even. Just don't state the relevence at first. If it's completely obvious by the description, make it a bit more vague. "Something about the colors drew MC's eye to the large painting in the corner..." You want to try to leave room for the reader to be able to figure it out, but you don't want to make it too easy. Figuring it out is half the fun of reading mysteries.