Thanks to all you good folk - I have looked at all your replies and advice - this is a subject I am totally unfamiliar with and some of the things that are mentioned I need to educate myself on. I have been able to resolve the problem this way - a friend of mine, Keith Murray has converted them for me, using Photoshop - http://goo.gl/LzLjIy - apparently it has something to do with the colour RGB when it should be sRGB, he would be able to explain better. It seems that RGB doesn't convert easily into Pictures2Exe ... it's all a bit beyond me, I'm afraid