firefox - Images not loading in most browsers

Since this morning I have a problem. Some images(not all) are not loaded throught many websites. They look like this(this one's from fb):

Same problem happens in chrome and firefox.

I did a scan with Malwarebytes and it found some infections which I deleted, but the problem is the same. I don't use any addons(had adblock but disabled it), and since the problem persists in firefox, too...

Try to get back configuration on IE like this:

Open the Reset Internet Explorer Settings dialog box. To do this, use one of the following steps. - Close all Internet Explorer and Explorer windows that are currently open. Start Internet Explorer.

• Note If you are running Windows 8.1 or Windows 8, start Internet Explorer from the desktop. Changing your settings will affect both Internet Explorer and Internet Explorer that you start from the desktop.

• On the Tools menu, tap or click Internet options. If you don't see the Tools menu, press Alt.

• In the Internet Options window, tap or click the Advanced tab.
• Tap or click Reset. If you're using Windows Internet Explorer 6, click Restore Default.

• In the Reset Internet Explorer Settings dialog box, tap or click Reset.

• Note Select the Delete personal settings check box if you also want to remove browsing history, search providers, Accelerators, home pages, Tracking Protection, and ActiveX Filtering data. When Internet Explorer finishes applying the default settings, tap or click Close, and then tap or click OK. Exit and then start Internet Explorer.

Source: http://support.microsoft.com/kb/923737

I would guess this is due to an AV; many anti virus programs include an Anti-banner function/module.

Or it's a browser plug-in. I know you said you don't have any addons, but start the browser in safe mode and see if that solves it. If so, you need to see if you actually do have any addon's (and that may be you didn't realise they were there) and disable each add-on one by one until you find the culprit.

You don't have any AV (for what ever reason) so may be some thing installed itself (virus/malware/other) without your permission... Just because you ran a Malware bytes scan doesn't mean it's defiantly going to pick up this issue, especially if the AddOn isn't actually doing any harm (ie, if it's blocking banners)