Download apache, and then follow the guides and everything to set it up. And then move the file/picture, or anything into the correct folder. And then the image being hosted will be http://your_ip/image.jpg or w/e
If you want a .com address then you will need to register a domain name. Then set up a web server on your computer. Then point the dns server to your computer. Seems like quite a bit of work just for a picture.