Jen, here's how to upload pictures from your computer:
In the toolbar above the message box, click on the paperclip icon. This will take you to a new tab or window called "Manage Attachments." Go to the section that says "Upload File from your Computer." Choose up to four photos, then hit "upload" (way over at the right). Be prepared to wait a while if the files are large.
Now the confusing part. You won't see the pictures, because they haven't been inserted into your post yet- they're waiting in a queue. Place your cursor in the post where you want the picture to appear. Then hit the paperclip icon again. This time a drop-down menu will appear, which should have all the pictures you uploaded (if not, they're still uploading). Choose the one you want. You still won't see the picture, but you should see something pop up into the post indicating an attachment. Repeat for each photo.
You're done, but I would recommend using "Preview Post" first to make sure everything is the way you intended. Now you should actually see the pictures. Last, hit "Submit Reply."
Here are some general instructions for using the app. I wrote and tested them on my iPhone, so I would appreciate feedback if anything is different on an Android platform.
I have had trouble recently with internal links on the app, so if the link doesn't work, go to the "Browse" menu, select "Fiberglass RV Community Forums," "Forum Admin, News & Announcements," and scroll down to the thread "Help with FiberglassRV App."
Hope that helps!