Here's something about me that only some of you know: I enjoy putting together jigsaw puzzles. I know, it's a bit archaic in today's digital world, but there it is. I'll admit, I don't jigsaw as frequently as I did growing up, but every once in awhile I get the urge.
Here is my most recent accomplishment, a PhotoMosaic puzzle, where the puzzle is composed of a whole bunch of tiny pictures which create a larger image when seen at a distance (in this case a wolf):

As someone told me that 'only a crazy person' would try to put together such a puzzle, I offer proof that it can be done and a few pointers should you wish to try it yourself:
Hint #1: Turn all the pieces face-up and sort by major color groupings (in this case I sorted by bright/white, dark/black, and everything else). This puts a lot of pieces that fit together closer to each other. Pick a portion of the puzzle that has a lot of a given color and start with those pieces (in this case I started with the wolf's snout, which had a lot of whites and light-blues).
Hint #2: The tiny pictures are configured in a grid pattern. This means that all the puzzle pieces in any given row or column, will intersect the grid pattern at the same width or height as every other piece in that row or column.
Hint #3: The tiny pictures are all right-side-up! This gives you a huge advantage as you can pick up any given piece and know its orientation relative to the rest of the puzzle (in most cases at least; it won't be clear on some pieces which end is up).
Hint #4: When all else fails, look at the picture on the box. The tiny pictures are even tinier on the box, but you can figure out a piece's relative position this way.
Hint #5: As you get closer to finishing the puzzle it becomes extremely helpful to sort the remaining pieces by shape. This makes it especially easy to fill in those one-piece holes that invariably remain.
With these few tips you should find that these puzzles are really not much more difficult than your basic jigsaw puzzle. Happy puzzling!