One of the foibles of 'free' anything, is that there can be certain limitations. Unfortunately Postimage.org is not alway running 100%, especially late at night when they are doing system wide backups...
Posting pictures is usually simple. If you get confused, just slow down, read the screen, if it gets to be overwhelming, just send them to me and I'll post them when I can.
Click 'add image to post' (above the box your are typing in when posting)
Choose 'computer' or 'web' (where your pictures are, to the right of Upload Images on new window)
Click 'Browse...' to go to the folder where the pictures are on your computer, or on the internet, hold down the control (ctrl) key while you click on your pictures, do about 8 at a time.
You can leave resize alone at the default, or change it, it just changes the size of the pictures for faster viewing/upload, 8 mb per file size limit...
Click 'Upload It!' It will insert the code for the picture below the line you are typing on, you can hit 'Post' (below the box you are typing in) and you're done. If you hit preview, be sure to scroll down and hit 'Post' when you are done previewing.