A small artwork purchased at an East Vancouver garage sale for just $50 is expected to net a small fortune at auction after experts confirmed it was painted by the man who inspired the legendary Group of Seven.

It took two months for contemporary arts specialist Kate Bellringer to confirm her suspicions about the piece, but numerous Tom Thomson experts all agreed that it was created by the iconic Canadian painter.

The lucky buyer brought two dirty artworks in a shopping bag for appraisal at Maynards Fine Art and Antiques after picking them up for $100 in January, but almost didn't show the Thomson because it didn't seem very valuable.

"He saw them in the yard sale, didn't know that they were authentic, but he said it was an impulse purchase when he decided to buy them," Bellringer told CTV News.

But when Bellringer saw the oil painting, she had a "gut feeling" it was something special. After some cleaning, Thomson's signature could even be seen very faintly in the bottom right corner.

Art experts believe the painting of Ontario's Algonquin Park was created in the spring or summer of 1915. It will go up for auction on May 16, and Bellringer estimates it will sell for between $150,000 and $250,000.

Just a few years ago, another unknown Thomas painting sold for $170,000 at auction after spending years hanging above a television in a New England home.

The second artwork in the garage sale haul also turned out to be a product of the Group of Seven: a 1901 watercolour cityscape by Frederick Horsman Varley. That painting will also go to auction next month, when it's expected to fetch between $4,000 and $6,000.