How do you change one type of image to another type?

depending on your Operating System you may be able to use paint brush within Microsoft Windows. The best program I have used for photo manipulation is Adobe Photoshop. It's relatively intuitive and allows you the ability to edit photo's and export them to a gif, jpeg, or bmp with different types of compression so it will take up less space on your web page. If you don't have Photoshop you can always use the software at this site: http://www.coolutils.com/PNG-to-JPEG download the free download and convert your image.

I hate it when I accidentally refresh and lose my post like I did this one and then have to start over. Micrografx Picture Publisher is great. It was bought then known as Corel Picture Publisher. I don't know if it is still available. There are some great programs available at http://www.freeserifsoftware.com/ and possibly you can find something there that will work.

You could easily do that with ACDSee.The application has this "Convert" option in the "Tools" Menu. Hope this is helpful to you.

Any of the options given would work. I would like to recommend the program Gimp - it's a raster graphics editing program similar to Photoshop, but completely free.

I prefer to use Linux, is is simple in linux, using convert command, it just do what you desired to do. Convert aaa.png aaa.jpg

I often use ACDsee to convert it.I think ACDsee is easy to use,so i recommand you use this tools to change you image/picture.of course,you can use another tool,just like Xnview,and xnview is very samll,and it's a free software.but it can support kind of pictues.