There is no need to download the AdBlock Element Hiding Helper - but you should (obviously) have AdBlock Plus installed on your browser. It's an excellent tool, so if this Twitter issue is your introduction to AdBlock, you'll almost be glad for the Twitter annoyance.

Resist the temptation to click the AdBlock icon in the browser bar; in this case, the Easy Create Filter will only block one image at a time.

In the Chrome browser, go up to Window > Extensions to open your Chrome extensions on a new tab.

You'll see AdBlock Plus in the list (as above). Click AdBlock's Options.

Click the tab Add Your Own Filters.

The tab for Add Your Own Filters will have a line where you'll add:

twitter.com##.is-preview

Then click the + Add Filter button. And that's it!

 Next page: Use AdBlock to hide Twitter preview images and videos in Firefox (3 pages).

In Firefox there are a few more steps than with Chrome. Start by going up to the Firefox drop-down menu under Toos and scroll down to AdBlock Plus > Filter Preferences...

You'll get a new window: AdBlock Plus Filter Preferences. This window shows three tabs across the top. Click Custom Filters and then click the Add Filter Group button.

There is no need to download the AdBlock Element Hiding Helper - but you should (obviously) have AdBlock Plus installed on your browser. It's an excellent tool, so if this Twitter issue is your introduction to AdBlock, you'll almost be glad for the Twitter annoyance.

Resist the temptation to click the AdBlock icon in the browser bar; in this case, the Easy Create Filter will only block one image at a time.

Previously: Hide Twitter preview images and videos using AdBlock in Chrome (1 page).

After clicking Add Filter Group you'll get this new window where filter groups can be listed. If you want to label the new filter you're creating, double-click the "New Filter Group" text and it will highlight so you can give it a name. (Extra points for more creative names than the one I chose.)

Click the filter group to highlight it, then hustle your mouse over to its Actions drop-down menu to select Show/hide filters.

 Previously: Hide Twitter preview images and videos using AdBlock in Chrome (1 page).

After you clicked Show/hide filters, the window splits into two panes (above). Click the button in the upper right of the window that says Add Filter.

An entry field will appear in the "Enabled: Filter rule" box. That's where you'll paste this code:

twitter.com##.is-preview

(Yes, it's the same code as used in the Chrome/AdBlock hide Twitter previews technique.)

To finish, click Close. And you're done!

 Thanks for the tip: @xabean