You can also load many at once if you select multiple at one time or you can use the FROM PC button repeatedly.
Your broken link for 522281 occured when you deleted the attachment from the box below the post after the thumbnail had been inserted in the post. When deleting an attachment, you need to delete it using the delete button associated with it and then delete the ATTACH bbCode text in the body of your message. When going "under the hood" like that it may be convenient to click on the symbol at the far right of the tools that looks like a page with a wrench.
