@LittleAnnie, you can just click on the 'Chose File' box below each post box and then find the image you want in your files, (on an IPad or IPhone, it will be under Photo Library, on a PC, look under your 'Pictures' folder.)
Once you find the one you want, click it to upload then scroll down to hit the Finished/submit button.
I always hit the preview button first to see if the post looks correct before submitting it.
You can try it out by adding a photo for your profile picture to replace the default acorn if you wish.
Just go to your profile and click the 'Change your Public Profile', scroll down to find that same 'Chose File' and repeat steps described above.
