Before you consider whether to embed images into your forum post, alternatives are
in posting a reply or new topic, attach images
–provide web links to images
Either join a permanent site for hosting images or look for sites that offer some number of days where the image can be viewed by forum users
I chose tinypic.com
You can create folders to organise your photos from friends to forums etc.
After creating an appropriate folder and uploading an image, I prefer jpg to condense size click on it to get the larger image
Next right hand click (for a right handed user) the actual image and grab the url for the actual image
This is likely to differ from the link showing in your address bar.
Next in the forum post in the normal text area I write, with a tweak to help those with smaller resolutions
[img width=128 height=80] the copied url to image [/img]