
Hi Marci, found this in the FAQ's this will explain better than I can.
Quote:
To attach a file to a new post, simply click the [Browse] button at the bottom of the post composition page, and locate the file that you want to attach from your local hard drive.
Only certain types of files may be attached: these are the valid file extensions for files to be attached to this forum: bmp doc gif jpe jpeg jpg pdf png psd txt zip.
After posting, the attachment will show up in the body of your message. To view the contents of the attachment (if it is not already displayed) simply click the filename link that appears next to the attachment icon

.
I save my images between 400 and 500 pixel. Kathy