How to build a sprite from a very large image
IT DOESN'T WORK IN THE JAVA PLAYER.
Thanks to B-Reyn428 and its very nice project http://scratch.mit.edu/projects/B-Reyn428/84741 and to Jens and its interesting way of creating a large explorable image http://scratch.mit.edu/projects/Jens/27625 by using four different sprites, I created a single very large sprite from a large picture.
You can explore the image by moving the mouse close to the borders of the Stage.
To create your "huge single sprite" just follow these directions:
1- follow B-Reyn428's directions in his project http://scratch.mit.edu/projects/B-Reyn428/84741 to create a very large sprite with the picture of the Scratch interface (don't care about this, we are going to remove the picture soon)
2- cut your very large picture in 480x360 squares (or smaller) as Jens did in his project http://scratch.mit.edu/projects/Jens/27625 (you can see the pictures in the 4 useless sprites contained in the project). You can do this with you favorite software, if you don't have one, I would suggest the free Screenhunter application.
3- edit the costume of the very large "Scratch interface" sprite and import the single pieces of the image you cutted in advance, then put them aside (the 1 pixel border around the images will disappear as soon as you close the editor)
NOTE: Enlarging a large sprite is not allowed by Scratch. If you want to enlarge it you can use brinjal's strategy that he describes at http://scratch.mit.edu/projects/brinjal/1508937 (it works offline too)