The resolution stays the same for me when I zoom in - the blocks just get bigger, but don't resolve to anything smaller making it look hugely pixellated. :(
By squares, I mean the square map areas, not individual blocks. I don't know if the map shows exactly the same for everyone but if it does; there are 4 black squares to the right of where I am right now, followed by a regular 'lit' square, followed by two 'shaded' squares.
The 'shaded' areas seem to be happening since Ant updated the plugins so there seems to have just been a change in how the map renders. So eventually the whole map should be more like that I think.
I have always assumed that the blocks on the map represent the chunks in the world, which could be 16x16
~~~~~~~~~~~~~~
everyone else: I came to find out about the grey shaded bits and you have no clue :(
maybe they are bits that have been explored but not visited recently?
That yellow 8px square in the center is the size of a 1x1 block... but it's actually representing a torch (which is much thinner than a block).
I guess you can say, every coloured square on the map is a single block, but it's colour may be different to it's actual colour based on having something on-top of it which is actually smaller than one block (torches, signs, doors, ladders, flowers, etc).
Oh, and also in-game the blocks are not solid colours, or sometimes not even close to those colours.
Still it looks like the new darker map images are improving things - if you head north from the Citadel until you reach another shaded area - the dark green in there is grass, which used to be coloured purple as you'll see if you look at the surrounding areas.
