Convertron v1.0 by fieserWolF released on April 18th, 2017 - This program for Windows is a graphics tool for converting graphics images (png, tif, gif, bmp, jpg) to Commodore 64 Koala or Hi-Res format.  There are lots of options for optimizing the image using various effects and palettes.  The results are impressive and with a handy preview feature it's easy to quickly try various configurations before saving.