bmp to scr conversion is almost certainly graphical export from BMP raster graphics, but to what type of .scr file is a bit hard to tell, considering the sheer amount of different SCR file types that do exist.
If you need to save your graphics to some rare .scr file, it might be best to use some dedicated graphics converter with broad format support, such as XnView as it gives you the highest chance to find the exact format you need.
Updated: September 12, 2023