What is the Difference between Texture and Image?
An image (2D) is the projection of a natural scene or man made drawing on to a plane. The output of an optical sensor when displayed is an image. 

Texture is a picture created by repeating a basic element called 'texel'. The texel can be a natural image or an artificial one. 

The edge detection algorithms works on matrices. So if it is a normal image or texture image, you can do in the same way. 

In texture images, recognizing the texel makes the rest of processing easy. Because you need to work on a smaller sized matrix.