For iPhone/iPad it is essentially the same process. Click On 'Attach files' button at the bottom, select your pic, click on the 'Done' at thee top right of the pop up window, then the file will upload. Once uploaded select 'full size' or 'thumbnail' then click on 'Post reply.
I will try to help here. To re-size using my iPhone I do the following: Go to my photos and touch a photo I wish to use. Email it to myself. When I hit the send button small, medium,large and actual size will come up. I touch the medium. When it comes in my email I open it and touch the picture. On the lower left on my screen it will say “save image”. Touch that. It will now be in your photo album to use. Maybe there’s an easier way . That’s how I do it.
1. Find the file on your PC which you want to post. Double-click on the file.
2. Windows Photo Viewer or Paint will display the file. If it is Windows Photo Viewer click on 'Open' then 'Paint'
3. Now you're in Paint (If you don't have Paint, I believe it is freely available from Microsoft)
4. At the bottom of the screen you should see both the dimensions of the image and the size.
5. Optimal size if less than 1MB, Optimal dimensions are between 800x____px or 1024x___px.
6. If your image is larger dimensionally:
7. Click on View' in the top menu bar (you may have to click on 'Home' tab first)
8. reduce the horizontal dimensions until you are between 1024 and 800 px for the width (first number)
9. Save the file.
That should do it. Try that out and let me know.