I am getting an "HTTP error" when I try to upload an image greater than 150 or 200 kb in Wordpress. I've been able to upload in the past & this just happened. I've tried various online suggestions to no avail.
Apologies on the WordPress error you're seeing. Ever since WordPress updated to version 3.5.2, there apparently has been an ongoing issue in how uploads have been handled. We currently have our systems team investigating the issue, but if you want to get around the problem for now, I will suggest that you turn OFF mod security. You can go to our Disable mod security article in the Support Center. However, I do suggest that once you finish your uploads, that you re-enable mod security. That way, you are still protected from the ongoing brute force attacks. Our apologies again for the hassle to get around this current update.