Incidentally - if you want to embed the photos so they display - you go to the paperclip at the top (when in "Go Advanced") and select the links there and they will paste a link number in your message - then when you press send, the photos appear in the message box instead of as links at the bottom
However if the pixel size is too big they stretch the forum so they may need shrinking - in Windows it's easy - you right click on the photo and open with Paint, select "Resize", Select "pixels" rather than percent and change the number in the top box to 650 or 700. Then do "save as" - so it saves it to where you want, but keeps the original in tact. There are various apps for resizing photos on phones etc as well.