My grandmother has this old painting that she got from a friend by someone named D. MAN I thought I found a painter with the same name named l. d. man but I'm not sure trying to find the name and price of the painting it's a boat following another boat in the water going to a town and the other...

I have a painting of a scene of a canal in venice. The signature on the painting is "Poattie" How can I find out if this painting has any worth, Thanks

Hello, I'm trying to identify the attached picture. I think that it is from the first half of the 19th century (oil on canvas) and a self-portrait of the painter himself. If someone can help me to identify the painter on the picture it would be grate. Thanks in advance, Freddy