That's where I verified 10 file attachments (total) and 3Mb (2.86 Mb) file size. That doesn't explain why I cannot post a file here for similar reasons. The only difference is that the error message says I'm trying to post a file larger than 1 mb instead of 2.86 mb and that is before I've even selected a file. Curious.
And you said this just appeared out of nowhere? Could you inquire with your host as to if they've preformed some sort of update? Id242 suggested trying to use ImageMagic vs GD and suggested that something "Server Update" related could be at fault with the GD image library.
O.K., I just talked with my ISP (Network Solutions) who tell me that some programming needs to be changed in order to make this work and that I have to pay them (or someone else) to do it.
I think I figured it out. It's been a while since I added attachments to posts, but I still should have remembered that I need to find the file before adding the file!