Get image data: returns either (csRGBpixel *) or (unsigned char *) depending on format.
Note that for RGBA images the csRGBpixel structure contains the alpha channel as well, so GetAlpha (see below) method will return NULL (because alpha is not stored separately, as for paletted images).
Create a new iImage which is a mipmapped version of this one.
'step' indicates how much the mipmap should be scaled down. Only steps 0, 1, 2, and 3 are supported. Step 0 returns the blended version of the image without image being scaled down. The new image will have same format as the original one. If you pass a pointer to a transparent color, the texels of that color are handled differently.
This method will allocate a respective color component if it was not allocated before. For example, you can use this method to add alpha channel to paletted images, to allocate a image for CS_IMGFMT_NONE alphamaps or vice versa, to remove the image and leave alphamap alone. This routine may be used as well for removing alpha channel.