The second page has an interesting workaround at the very end (the SetEnvIfNoCase line). Anyone with the issue care to try that? (Note that the "ot buffer..." part should be part of the previous line.)
I recently moved hosting companies from one VPS to Linode. After the move everything was working fine, but I started having members complaining that some images were not uploading properly.
They would upload an attachment (image) and the progress bar would hit 100% and then nothing would happen.
After a bunch of researching, I changed the following settings for PHP and MySQL to match my previous VPS. I'm unfortunately not sure which one was successful in fixing the problem, but wanted to post here (and a few other related threads) to share that this worked for me!
memory_limit = from 32M to 158M
max_allowed_packet=268435456 to max_allowed_packet=64M
wait_timeout=10 to 45
(make sure to restart your services after you make the changes)