If I want to post multiple photos in one post, I click on Create Mail within my e-mail program.
I write what I wish in that program, and list the website addresses of each photo I wish to include...one after the other on that "new letter" I've created.
The reason I do that is if you try to do it within the post, often you will "time out"...and lose all your work.
When the post is completed and all photos are listed within that "new letter", I click on Edit, click on select all, click on copy..
THEN I go to the Forum, open a new posting insert the subject in the proper line. I then click on Edit within the Forum posting and click on Paste and there it is, in it's entirety!!
Click on Preview....and you'll see your whole post, including all photos. Close that window and click on Reply to Topic to post it.
Hope that helps everyone. Any questions, please ask.
Have a wonderful day!