If you have the time to upload a picture i reccomend using
http://imgur.com/
-Pictures can be uploaded from pc folders or internet pictures.
-Usable for uploading to forums.
-Will not be replaced.
For quick screen share's i reccomend using
http://snapcr.net/download.
-Pictures can be uploaded from selecting an area on screen.
-Pictures might be replaced by others and are not permanent.
-Usable for uploading to forums with risk that the picture might be replaced soon.