Hi Rebecca, you can test it here on this thread. At the bottom left, click on the green area that says Upload an Image, choose the photo from your computer and open it. You will then see something that resembles this photo I've just selected from my laptop:
Once those letters, date, your name, numbers, etc. show in your post you can click the green Preview area to see your photo and then click the green area that says Finished.
Try it out ... it's really easy once you get used to doing it.
Oh, for uploading a photo to the database, you will first have to find the plant in the database that you want to upload a photo of and click on the left side blue where it says Add an image. You will get the directions and once you've added the photo, it will go into a waiting line for the database administrators to approve but you will be notified once it's there.