Usually we post pics, but not always. Some of us are very secret. In fact, mostly you never know who they came from. I don't object to you posting pics of every block.
I mix it up, and use cloth I have that meets our basic plan. In this swap, with us using one block for everyone, using differnt colors will assure that every block, and indeed every quilt, will be unique. It's OK if you do them all the same though.
I've gotten the feeling from distributing blocks, that 60% use the same exact fabric consistently, and 40% use diffent cloth, to variying levels of "matching". Some look differnt from block to block, even in the block they choose, and others use exact same blocks, but maybe various cloth withen the same hue of a color. It's all good.
I personally use all kinds of cloth, and even change my blocks sometimes. I get bored easily, and the artist withen me insists on expressing herself even in quilting. I suppose I could do them all the same, but in this swap I'll use our design, but change my greens and whites from block to block. Probobly none will be alike colorwise, except greens and whites. I've got lots of medium greens, and various textures and patterns of whites I'm looking forward to playing with.