How would you translate this

[NeneaNicu]

Cette toile a déjà pris de la valeur

[Vereschagin]

How about "This painting has already increased in value."

[FrenchByte]

Probably that, with the 'increase' and 'value'. It makes the most sense.

[jolynnedougherty]

Or maybe "This painting's value has appreciated."

[FrenchByte]

This canvas (or painting, though toile is canvas) has already taken (or gained, I think that is more grammatically correct) value.

Or, "this canvas has already gained value"; that is the closest I can get.

[porkcfish]

This canvas [painting] has already gained in value.
This canvas has already taken on value.