You can also upload photos via http://imgur.com/ without registering. After that copy 'BBCode (message boards & forums)' given in the website and paste here on IF.
You may want to register on any of these sites. Uploading an image without registering usually means that the pic will be removed after a certain time period. I believe it's 24 hours for Photobucket and something like that for Imgur as well.
Cricket
Anupamaa
