Open your photo in Paint before you upload it. When it opens, this is how large it will be if you upload it.
Alternatively, you have 20 minutes to edit your post. Upload your photo, check the size and if it's too big, use Paint to reduce the size, save, and upload the smaller photo. Click Save Changes. Then click the edit button again. Click "Advanced Edit". Delete the large photo. And you delete the attachment .jpg as well. To do this scroll down the page a little and click on "Manage Attachments". Choose the bottom jpg and click "Remove". Then click Save Changes.
Easy to do! It doesn't take but 2 minutes once you get the hang of it.
Thank you Christine.
What you don't tell us is how to know in advance how big the photos are going to turn out when we post them, and if we have posted big pics, the thread is stuck with them.