I’m running XP.
I switched the security level to “allow all” and still I could not upload images.
So I removed Comodo.
Went back online and I was able to use those sites.
This is an intermittent problem I’ve been suffering from for the past two years, way before I switched to the Comodo firewall, so I don’t think it’s specifically due to that. I’ve also got a second machine which has a built-in Nvidia hardware firewall and that suffers from the same problem too.
I’ve been able to overcome it in several ways, some more drastic than others. To deal with the least draconian methods first though:
If you’re running Win XP Pro, login with your other Administrator account. It’s not always guaranteed to work, but it does most of the time.
Run CHKDSK from the Recovery Console.
You can install the Recovery Console on your hard drive by inserting the Windows installation media, cancelling the menu and then going to Start → Run and typing: x:\i386\winnt32.exe /cmdcons (where “x” represents your CD/DVD drive) and click OK. When you reboot, you’ll get a menu instead of the usual splash screen. Choose to boot to the RC and then type the figure “1” and hit Enter. Next, type in your Administrator password which will take you to a C:\Windows prompt. Type: chkdsk c: /p and hit Enter.
Delete the User profile for the account which is suffering the problem. You have to do that in Safe Mode because the file is locked in normal mode. This is the most drastic solution because it deletes all your custom settings and any emails you have stored, so backup those first. User Profiles are located in System Properties → Advanced.
But as I mentioned in the beginning, the problem is intermittent. It will manifest itself spontaneously one day and disappear the next, or may hang around for days on end. I’ve scoured the web, but have never found a permanent solution so far I regret to say.