SukiSatyricon

Hello, I am totally new to any type of building so I'm reaching out for a little help. I am bascially trying to make a wall mural by creating an object, then changing the size and adding a texture. The texture that I am adding is a .png file that I have cleaned up with a transperant background in Photoshop. The end result I'm getting looks good but I am still getting a small line around the object itself, not the image. Is there a way to get rid of the line, i.e. make the object itself 100% transperant without affecting the texture? I would greatly appeciate any assistance even if it is pointing to me to an online tutorial. Thanks, Suki