Thanks I will give it a go.
To clarify my thumbnail comment – In the featured image section it is possible to click ‘edit image’, thus opening up a cropping and editing window. In that you can crop the image and select a box on the bottom right of this window that says changes will apply to thumbnails only. When you confirm, the cropped, thumbnail image then shows in this edit window. That crop is what I wanted for the Pictorico front page post image but it does not seem to be able to understand that I have edited a thumbnail version of the photo…I don’t know exactly. It all seems more complicated than it need be.
But thanks for your help.