How do I change pictures to jpeg?

Open the image using an image editing program (I recommend Gimp or Photoshop, Paint if in a pinch) and choose to save it as a jpeg file.

open a picture with a graphics editor such as gimp

http://www.gimp.org/

click File> Save As...

In the save as window look for a "File Type" drop down box and change it to jpg, jpeg

you could use zamzar a ONLINE converter you just upload the file and download the jpeg

There are many softwares to change file type,try this website www.software.com