The file 'file_0_' exceeds the defined ini size

That is the error I get when I try to upload an image of about 2000 pixels by 1200, despite the fact that I've set the settings WAY higher than that. If I upload a much smaller image, it works, but what's up?

Oops, sorry to leave out the fact that this is version 1.0beta on Ubuntu 8.04 LTS (Hardy Heron) (I had upgraded the kernel to get PHP 5.2)

I just tried uploading a JPG file, 3054 pixels by 2036 and it uploaded fine -- so I don't think the problem has to do with the file dimensions necessarily. What was the file size and type?

OK, then this is really puzzling, since the image I'm trying to upload is no more than 2,000 x 1200 pixels large and my settings allow full images of up to 5000 pixels on the longest dimension. Could it be that there is a MySQL setting that I need to change, I wonder? I have a plain vanilla Ubuntu MySQL installation, although I believe I followed the installation instructions on UTF-8, etc.