Cursed mage trapped in a painting

This is from the NaNoWriMo Adopt-a-plot folder where writers post extra plots they won't be using.

#13: "Your female MC [main character] is an art lover. She collects all sorts of random art and paintings from dusty little backstreet shops and her house is filled with her collections. One day she buys a painting which includes a robed figure. This robed figure is actually a mage who has been cursed by an enemy to be stuck in the painting until such time as something lets him out. The MC unwittingly manages to release him, and now a countdown is started. The mage has to find a way to break the curse and/or kill his enemy within a certain time limit or he will be stuck back inside the painting for all time. Our mage friend has two brothers, one younger, one older. They sense or otherwise find out that their brother has been released and show up on the MC's doorstep (because of course, being kind-hearted, she lets the weird stranger from the painting stay with her until she figures out whether to call the insane asylum or the police, or both) to help find a way to stop him from becoming art for eternity. The younger brother is obsessed with potions, but hasn't quite gotten a hold on his magic yet, so anything he makes is more likely than not to go wrong or just blow up. He's very hyper and tries a lot of wacky antics to get the original mage and the MC together. The older brother works with runes and tarot cards. He's dark, sullen, and will do anything in his power to keep his younger brother and your MC apart, because he doesn't find her suitable for some reason. The first mage, the one in the painting, manipulates matter and energy, which basically means he's good at illusion and transmutation. The only catch is, they can't use their powers in front of ordinary people who don't know about them. So until the MC finds out that they are mages (and probably hundreds of years old), they can't do magic in front of her.

"Will they find where the first mage's enemy is hiding? Can they break the curse in time? Will the younger brother blow them all to hell before they can get anywhere? These questions are for you to answer." -- Khetienn