Reading bmps - help!

    //this is a 24bpp bitmap, so I get the actual pixel width    byteWidth := header.gWdith * 3;    padWidth  := byteWidth;    //i increase the size until it is on a 4 byte boundry    while(padWidth mod 4 <> 0) do      padWidth := padWidth + 1;    //this is the actual image size with no padding    diff := header.gHeight * byteWidth;    //this just sets an array to be the size of the actual image    SetLength(imageData, diff);    SetLength(tempImageData, byteWidth + 1);    header.gSize := diff;        //I set the offset to be the difference between the padded width and the unpadded width    offset := padWidth - byteWidth;    saveCursor := screen.Cursor;    screen.Cursor := crHourGlass;    //loop for every pixel of the image    for index := 0 to (diff - 1) do    begin      //if it is at then end of a line (before the padding), then skip past the padding      if (((index+1) mod (byteWidth)) = 0) then      begin        seek(myFile, filepos(myFile) + (offset));      end;      //read in the byte      BlockRead(myFile, imageData[index], 1);    end;

scanlinelength = (width * bitsperpixel) >> 3;stride = (scanlinelength + 3) & ~3;padding = stride - scanlinelength;