There is a program called gimp, it's free to download and use. There is also another program call photoshop and I think it cost money so gimp is the one that you may want. And about downloading maps with Mac, I have window but I think I can able to help users with Mac. First, press the link to the download, second, press download to download your map(s), third.....press run I think and then after that, save the map in the terrains file inside the feralheart folder, (ex: map'sname.fhm goes to terrains file)
