IMG is an image file and you can not cut this in 700 mb parts to fit the cd’s but you can extract it and if is a dvd you can convert it to svcd .
WinAvi like most of the video converters have included a splitter.It’s a new UltraIso if you want to try it here is a link: www.9Down.Com or MagicIso.If you have problems to extract the file change the extension from IMG to ISO and extract it.