Converting PNG to JPG/GIF

I understand that inkscape currently doesn't allow exporting to JPG/GIF. (0.46) I hope this is being considered for future versions. I have googled and read other answers here at launchpad. I know you need to use some other program to convert it. That is what I am asking, what program should I use to convert my PNGs. I require a program that is free and is good. (Users like it, good reputation... etc.) (Not a random convertor tool on Google) I am seeking something other then GIMP. Irfanview I have tried and I am not satisfied with the non-transparent background. I require a program that can convert my images to either JPG/GIF without losing any quality or color. I require conversion because I am concerned with PNG compatibility issues on the web. I believe PNG is a newer format and not as widely supported as GIF.