Why does RasTools accept only BMP formats and not TIF or JPG?
Image formats such as TIF and JPG are not accepted by RasTools because Windows reads BMP formatted images more efficiently than other image types. This is because Windows uses the same byte-order and row-order conventions for the definition of BMP files and internal image buffers. In both the external BMP and the internal Windows format, the first pixel in the definition is at the lower left corner. Pixels are defined in rows with the last row being the upper-most row in the displayed image. So a BMP format image has a significant speed advantage over other formats in that the image bytes can be read off the external file and into the internal DIB with no changing of their order. Both TIF and JPG define the first pixel in their formats as that at the upper left corner. Row after row of pixels are defined, with the last row being the lowest row in the image. When TIF and JPG format images are read by a Windows program, the rows must be flipped (the last row of pixels must be first, etc.
