Select "Go Advanced" (even if you have already begun typing, it will carry over your text). Below the text box, you will see a "manage attachments" button. If you click it, you will get a box that allows you to browse your computer to select attachments (you can do this multiple times). That box will also have a list of file name extensions, the max file size in K and the max pixel size for each different type of file. The most common is .JPG files and they are limited to 145K in size and no pixel limits (this is much more that previously allowed, which was about 78K if I recall). I always resize my pics to 600x800 or less and use a fairly high compression factor to get less than 78K. Guess I won't have to compress so much now.
Attaching your pics puts them on this web site, they will never go away unless you delete them (which you can thru your user control panel - attachments). If you use the little yellow "postcard" icon (with the mountains) to link to your pic, they you have to have your pic hosted elsewhere (or on this site previously). Problem is, the host sites seem to lose your pics, you give up your membership, whatever, and the linked pics disappear, and we don't get to see them. Some discussion boards won't let you link to pics for this reason, but insist you upload them.
Uploaded pics appear as thumbnails, and linked pics appear full size.
Charles
Below is an uploaded pic as a thumbnail (the thumbnail is created automatically by this discussion board's hosting software.) Also below is the same pic, which I created a link to, using this boards software to host it.