Upload to http://imgur.com/

Then click on and copy/paste your image link between the two [img] tag.

dropbox is even simpler

put it in your public folder, right click on the image to get the public URL and use that as source for the image you post.
downside is that if you remove your image from dropbox it won't show anymore on your posts, upside is you have more control and less hassle

Sorry to bring up an old topic but I am having issues I keep getting the red image proxy invalid image

Same thing happens to me sometimes, probably just the file size as the proxy blocks the images if they take too long to load up. Best to either re-up or just post a direct link to the image.

I ended up getting it right before I cam back to check this thread. The link on the side of Imgur does was for the picture of the whole page and not just the image.

find a picture u want on google
and u open the image then copy the link of the image
then paste it using format

seriously i dont know how to add a picture in my account..

If I recall correctly, there was an hacker last year which managed to abuse the forum by using avatars.
Not sure how that's possible, but they have been disabled since.

I wonder why it won't except onedrive urls