Upload to your computer? Well, first, make sure the picture in the the SD card memory, and not the system memory. If this is not the case, it is simply a manner of clicking the picture you want in the 'view photos/video' section, and then tapping the icon on the menu that appears to copy a photo from one source to the other. Once this is done, put the SD card into the SD card slot in your computer, if it has one. From there, locate the folder where the file/s is/are contained.
If you don't have a SD card slot in your computer, you may be able to put the SD card into another device, and then connect that to your computer with a cable. I can't help you much with this aspect. Sorry.