A quick random test using Windows 10 without even looking at the file size.
Ok, so let us go through this. I clicked on 'Attachments and other options', clicked on Browse and chose from my pictures files the above image of a Bismuth crystal. I then added the above statement be cause it didn'tlike me posting a mesage without text, and pressed 'Post' (I think it is that and not 'Send'.
The image came up a bit bigger than my usual images, but pleasing all the same.
Are you adding a bit of text to your test posts Bob? I imagine you would get the same warning in red and pink if you tried to post a message without text, but maybe not?
One thought. Where are you accessing your images from? I access mine as mentioned straight from my 'Pictures' file. If you are trying to access them from your photo upload program (I use a Fuji Finepix and could access my images from the Finepix program) then maybe the Forum host does not like your photo storage program. PHP does not like some phone systems as demonstrated by the very small text, so maybe the same applies.
We will get there Bob. We will see your progress on Agincourt even if one of us has to go down to yours and etch-a-sketch images of her