How to change the picture format from RAW to JPEG?

I want to post pictures on tumblr but it won't work. How can I change my pictures for RAW to JPEG on my computer?

I have a Nikon D70s

Added (1). I'm still in highschool and I can upload them now but they are coming out so small. How do I make them bigger?

Convert them using an image converter.
Or you might have the option to save the files as a different format on your camera.
I have a Nikon too, good for you.
Hope I helped!

Am not awesome with computers. But I passed some exams. So try right click on the picture. Then go to properties. If that doesn't work scope around and look to see if you can find something related to it.cause it may by that.

(Edit) Just noticed you meant on a camera. Sorry can't help. But you could try putting them on a computer then changing them. Then putting them back on the camera

Read your dslr manual, it will be within settings on your camera

Use the software that came with the camera…

To batch process RAW images, I use Adobe Lightroom. If you are a student, you can buy it in the student store for under $100

If you want free, you can download Adobe's DNG converter. It converts RAW files to a generic DNG file which can be then processed by almost all photo programs

Use the program that came with your camera.